Corvette Running Hot - Corvette Cooling System Maintenance Running Hot C4 1992-1996

[@ozzstars_cars]

There is a lot of info in this video including the on and off coolant temperatures for the both primary and secondary fans. Also the proper antifreeze to use in the C4 generation Corvette. Thanks for stopping by the Ozzstar's Cars channel. Please ask questions and leave comments down below. Thanks! -Ozz (Glen) **Redline Detection SmartFit Cooling System Tester** amzn.to/2GXN4dm If this video has helped you out consider donating to the the channel with Paypal, thanks!: www.paypal.me/ozzstar

[@davemclellan6895]

A few points. The C4 Corvette cooling system is designed and extensively tested to run as high as 15 psi above atmospheric pressure. With the recommended 50/50 ethylene glycol and water the mixture has a boiling temperature of 268 degrees Fahrenheit. The system can handle temperature excursions to boiling because of the high mounted pressurized surge tank in the right rear corner of the engine compartment. When heated coolant expands beyond the volume capacity of the pressure system it goes into the unpressurized coolant recovery tank in the right front corner of the engine compartment. When the engine cools down the coolant in the coolant recovery tank is drawn back into the pressure system. The dual electric fans are programmed to turn on at around 220 F. In summary, 268 F is the number to remember not 212 F the boiling temperature of water at 1 atmosphere. Based on your story Corvette drivers are panicking when all is normal.

[@White91Z]

The final word from the man who would know. I just got my third C4, a 9000 mile 91 ZR-1. I Previously owned an 85 and 90 6spd ( not to mention my 70 big block car.) No cars are ever perfect but reflect the technology of the time. You pushed the envelope, especially with the LT5. What a contribution to the world of automotive engineering you made. Many thanks for lots of miles of enjoyment.

[@JoeGiz64]

231 the fans kick in on my 92 LT1. Was thinking of going with a lower temp thermostat.

[@donleblanc7223]

Thank you Dave for the clarification. I just bought a 1993 convertible, love it. thank you.

[@gordocarbo]

Lot of lt 1 new owners panick as they look at the needle on the gauge not the actual readout temps Thought LT1 fans came on at 228 perhaps higher?

[@nickjones1619]

My 87 is 231° also

[@HeavenReservation]

My old c4 96 version had a temp problem until we took the radiator out and clean out each fin. Worked fine after that. Thanks for the reminder.

[@bugeaterfan1950]

Been watching a lot of videos on C4 repairs and troubleshooting. This dude knows his stuff and explains things in a down to earth easy to understand way. Learned a lot about cooling systems today on my C4

[@wyattoneable]

I came for the Corvette, stayed for the information. I enjoyed hearing about the system from a fellow enthusiast. My 05 has been bullet proof but for some reason I'm looking for a second Corvette. I know, it's a sickness. Oh yeah, that design of the radiator is like a vacuum. Great job on this one Glen, good to see you again.

[@SmittySmithsonite]

Sweeeeeeet! Well I want to see the video of it getting driven or trailered home, Wyatt! :D

[@wyattoneable]

@@SmittySmithsonite (ha ha) My wife will kill me if I drag another car here. We have four now and I can barely keep up with the maintenance now, much less add an old Corvette. I need to buy Glen's 93 that's in this video because I know it has been well taken care of.

[@ozzstars_cars]

One can never have enough Corvettes, I'm down to two now. If I had more storage space I'd be dangerous.

[@SmittySmithsonite]

Ozzstar's Cars - You can always buy a storage tent or 4 at Harbor Fright ...😁

[@wyattoneable]

@@ozzstars_cars I have room to store your 2017 Glen. :)

[@wedabrowns]

New 92 C4 owner! So very glad I’ve found your channel!!! I know these are old vids busy still so very helpful !

[@ozzstars_cars]

Enjoy your new Vette, they are lots of performance for the money. The vids keep on giving! Stay tuned for more. 😉

[@davidnimby]

I will congrat, you have put up one of the very most complete and well described C4 videos Ive ever watched, many hearty thanks my brother , please keep them a coming ! Eh ?

[@ozzstars_cars]

Thank you Donald.

[@1teem]

As a former C4 owner (1989 vette, manual transmission) in warm California climate I'd say the best thing to do is put the gear into neutral and take your foot off the clutch when stopped at a traffic light, the temperature will drop from above 200 down to 190s or 180s within 15 seconds all the time. Not sure what to do if you have an automatic transmission. Also a good air filter, aftermarket air intake and quality coolant helps. Like you said, make sure the radiator and fans are well serviced. Mine never overheated and I drove it hard like a dog in the blistering heat all the time, I miss that car.

[@ozzstars_cars]

Less friction equals less heat. Keep it cool!👍

[@larsz5224]

First, Glen, good video, good info. I owned an 88 vette for 30 years. Setup included L98 auto, electric fan and electric optional pusher fan. I changed the thermostat to 180, replaced the 235 temperature switch in the side of the block that turns on the pusher fan to a 200 and added a jumper wire from the pusher fan relay to the main fan relay. That way both fans turned on at 200. Highway temp rarely over 180. In town and parades never over 205. The factory design just left too little buffer between operating temps around 235 to cracking the aluminum heads at 260. Hope this is helpful.

[@gofast160]

'93 LT1 I've owned for 24 years. Never saw a video talking about what you said as far as debris buildup on the radiator. Didn't think my car had it (very occasional driver) but looked in there and sure enough it did! Hosed it out per your instructions, runs MUCH cooler, temp didn't go above 213 sitting in traffic last night. GREAT video thank you!!!

[@ozzstars_cars]

You got it Jeff, the beer tip jar is open. Haha. Enjoy those cooler temperatures!

[@stuzman52]

That vette’s engine is really clean and I know you’ve taken good care of her. You had a lot of information in this video on the cooling system and will help other enthusiasts out there. Have a great one Glen!

[@ozzstars_cars]

Helping the youtubers! Hope you are staying safe and healthy Terry.

[@marcusweathers5867]

Cleaning my radiator out with a hose like you said 10 years worth of trash birds nest plastic bags everything from the road.. Now I finally hear my primary fan working again haven't heard it for at least 6 months.!! thank you again...great video!!!

[@ozzstars_cars]

Good news Marcus. 👍 Thanks for the comment.

[@justbop5518]

Thanks for this great video. I have been worried about my 92 C4 getting hot, but it runs less than 180 on the road. I always panicked when temp got to 210 in traffic because that was 30 higher than normal. Now I know that the fans haven’t even turned on yet. I used your paper clip to test the fans and blew out the trash from the radiator. Honestly, there wasn’t much. Thank you so much for your video. I subscribed and gave you a like!

[@ozzstars_cars]

Glad the video helped you Just Bop. Thaks for subscribing and liking.👍 If you get a chance you may like some of my other C4 Corvette repair videos. Take it easy. -Glen

[@RichardT-t1b]

Thank you, started have high temps at idle after perfect temps driving. The tip for the fan test was just what I was looking for!!

[@ozzstars_cars]

Glad to hear the video was helpful! Thanks for stopping bye. -Glen

[@giorgiocisilino4874]

Our damn mechanic put the orange antifreeze and i specifically told him to put the factory green coolant in our 89 C4 corvette ,and he laughed and said he never heard about a vette using the green stuff, but if he read the owners manual like we did, he would know. The mechanic is a hotshot and former gm mechanic but should of know better.Also you mentioned to use the proper coolant and like watching and learning from watching your informative videos especially on c4 corvettes.Keep posting as you help us all out and we appreciate them so much.

[@ozzstars_cars]

Thanks Giorgio

[@graphman8402]

How to keep your 1995 C4 LT-1 between 180F - 200F no matter what: 1) take primary fan off relay, and put it on a coolant (low) temperature switch, or a manual switch 2) convert to Meziere WP118HD Heavy Duty Electric Water Pump 3) get an all aluminum performance radiator After years of anxiety here in New Jersey summers, now NEVER A WORRY!!! IT JUST WORKS!!!

[@ozzstars_cars]

That is way more expensive and involved than necessary.

[@graphman8402]

@@ozzstars_cars not really, turning the fan on/off with a switch and relay cost less that $10; original plastic oem radiator leaked, why buy more plastic; original oem water pump died pissing coolant over my optispark, why let that ever happen again... imho... ymmv... cheers

[@porterscott8360]

I live in Arizona so needless to say its hot here. I have an 1987 Z52 that ran hot all the time. There were several things that I did to help reduce the high temperature issues. I changed the thermostat to a 165 degree instead of the normal 190 degree. I then put a high flow water pump on the engine, wired in a switch kit that allowed me to control the fans both primary and secondary, changed the coolant fluid to the GM DEX and finally removed the radiator and found all kinds of debris between the front of the radiator and the back of the condenser. My car ran previously in the 220+ degrees with or without the AC especially in traffic, now its runs without air on at 175 and with AC 195. Since this is an L98 it has the aluminum heads and steel block which can be prone to warping the heads. So far all has been great. I also just bought a three row aluminum radiator which I still need to install. Thanks for a great video.

[@ozzstars_cars]

Wow Porter sounds like you have been busy with that fun project. Thanks for the comment and enjoy your "cool" C4! 😁👍

[@larrybud]

Thermostat really doesn't matter as a practice to prevent running really hot. If it's at 230F, the thermostat is open whether it's a 165 or 190.

[@HowtoAutomotive]

Glen everything on my car is jumped of paper clips. Awesome and very detailed video👍

[@ozzstars_cars]

Here I was thinking you use butt connectors like a professional. 🤣

[@hasbeengood]

I miss mine... Good to see this beauty in the spotlight again. You would not beleive the "mud" i took out of the engine block and washing out the heater core and all the rest of the system. Good info indeed again Ozz.

[@ozzstars_cars]

Gotta keep the juices clean and flowing. 😉 Hope it's not snowing up your way yet?

[@hasbeengood]

@@ozzstars_cars Dude gimme a break! Winter is long enough as it is... don't make it start in October!!

[@leehayes4167]

Recently acquired a 1992 6 speed targa top with an overheating issue. Just the info I was looking for. I know what I will be doing as soon as it warms up outside. Many thanks.

[@ozzstars_cars]

Glad the video was helpful Lee. Let us know what you find.👍

[@jeffspicolli593]

Can't believe how clean your engine bay is. Not being able to shampoo LT1 because of the opti is a real disadvantage.

[@ozzstars_cars]

All cleaned by hand with a towel and detail spray. BTW you were awesome in Fast Times at Ridgemont High. Ever see Mr. Hand around?

[@jeffspicolli593]

@@ozzstars_cars Unfortunately my pal Hand passed away. What detail spray do you use?

[@ozzstars_cars]

@@jeffspicolli593 I use Garry Dean Detail Juice and the clean and prep to remove the real dirty greasy stuff. detailjuice.com

[@jeffspicolli593]

@@ozzstars_cars Excellent. Thanks. This is going to be awesome man.

[@ianm9853]

Helping keep my 93 in good condition man, thank you!

[@ozzstars_cars]

Enjoy your car!

[@randallwilliams595]

Appreciate it, learned a little more about the LT1, I wondered about the high coolant Temperature and the head gaskets. Thanks

[@ozzstars_cars]

Glad to help!

[@ErnestoValdezJr]

Thanks for the video... just bought my first Corvette and it's a 93 C4 as well. I did notice it heating up but then cooling down. Thanks for the cooling system walkthrough. I'll be checking all this stuff. Again, great video and explanation. The "that's what she said" line made me LoL!

[@ozzstars_cars]

Enjoy your new ride!

[@briancarrarini6069]

Thanks for the info, just purchased an 89 c4 running at about 218 degrees. I'm going to get it up on the ramps and clean out the radiator. Thanks for such great info

[@SteveRobReviews]

I look buffed in a wet suite :) The old plastic bag in the rad does it every time. Nice and clean engine bay 👍

[@ozzstars_cars]

I bet the ladies can't resist ya Steve. 🤣

[@bartusher8865]

Thank you my 93 runs a little bit 10 minutes then shuts off and will not start the fans use to come on but I don't here them anymore. I will try all your tips and let you know .thanks again.

[@Bobby-ns7gn]

Glenn, Thank , thank you thank you !!! I have a 1989 vette Black convertible. I would run around town on a hot day and freak out. 220 and I could not here the fans kick on, so I would put on the air and the temp would go down below 200 even 190. I have done every thing you said to do in the pass, one time or another, but !...I had no idea about going between the radiator and the air coils ( what ever they are called ) and checking that area out and cleaning it. As soon as spring comes to Ohio and I get the car out, I will do that first !!! I bought mine in 92 in small town called Napoleon Ohio. They were super guys and gals there. The best part was, all there corvettes in the very large showroom had keys in them. And no pressure, they let you sit in any car and start it up. Soon as there is a car you would like to test drive, they get it out and zoom, zoom, you go ! I live in a small town called Kent Ohio, I actually drove 3 weekends there, Stayed in a hotel over night, till I got the one I have now. They even had some 50's and early 60's there, but those were behind ropes and if you are interested in one, the sales person were with you. Thank you again....Bobby

[@ozzstars_cars]

That's a great story Bobby! I really enjoy hearing the history of someone's car. It's a shame most are never told or dissapear with time passed. After all these years I bet you you will find debris between the radiator and a/c condenser. You're welcome for the vid and thanks for your comment. Hopefully you can post an update with the results you get. 👍

[@stevenrogers2457]

Hey man, thanks for all the tips! I followed your other video and fixed my climate controls, they work like new now. Now it's time for the radiator cleaning

[@keithlane4343]

Excellent info for the LT-1 C4s. I have a 1996 that runs great, but has the high temp issues you describe. When I was building '69 Camaros and racing them as a kid in the late '70's, 180 to 190 degrees was the normal temps. I finally got my C4 I always wanted, and it's running 225 -240 and scaring me half to death. I've been debating getting a thicker core radiator to make it drivable, but I want to make sure I'm bleeding the air out properly. Thank you for sharing C4 tech.

[@ozzstars_cars]

Have you checked and cleaned the radiator and tested both fans operate? Should be running around 200⁰ down the highway.

[@keithlane4343]

Yes, my friend from high school is a GM Tech and went to all the tech schools over the last 40 years. He has the wireless analizer that plugs into the OBD II plug under the dash. We found out , as you mentioned too, the digital gauge is more accurate than the analog, and the fans come on at the factory settings. I want to try to make sure it isn't air locked though, so I'm going to try to bleed of air in the cooling system possibly preventing correct coolant flow. I want to go for a ride without worrying about over heating. It's such a fun car. Has the feeling of my old Hot Rods , except it stops and goes around corners much better and burns half the gas.

[@Andrew-cq3hy]

I have a 94. The 95 and 96 did not run coolant through the throttle body. I replaced my hoses with the later model ones to bypass throttle body. It actually lowered temp just a bit and seems to be a little crisper on throttle response. This also removes several points of potential leaks.

[@ozzstars_cars]

I am interested in knowing how bypassing the throttle body coolant lowered the coolant temperature and changed the dynamics of throttle response. I've worked on cars for 30 years and have never seen that phenomenon.

[@nomad4731]

Glen, thanks a lot for this detailed and informative video. I have a 96 C4 and was having this high temperature situation. Found the problem and corrected it thanks to your info.

[@ozzstars_cars]

Good news Lou!

[@chrisbjarkman]

My 93 would run 200-220 in the FLA heat and add 10-15 degrees if I ran ac. I do have a fan mod so both fans would run even without the ac on. I had cleaned my radiator and assured zero debris, and had system flushed and serviced yet temps still seemed too hot for me. I then purchased a 3 core aluminum radiator and 160 thermostat. Now my car runs very cool (170-180 typically) with or without the AC even in the 95 degree days. I did make a YT vid on my channel showing results. Also as I understand things the digital temp indicates the temp at water pump while analog temp gauge is showing temp at heads. Thanks for the informative vid :-)

[@frankpavan3044]

Great Video .I have a 1996 automatic. Radiator fan on and off temperatures are something I will definitely look into. As well I will take a look at what may be stuck under there on the radiator and will try to wash it out. Thank you!!

[@ozzstars_cars]

It's most likely packed with debris. Let us know how it turns out Frank. Thanks for the comment. -Glen

[@barneythedog977]

I just bought a 95 with 44k. I withdrew some anti freeze and its pretty gritty and dirty, but how clean should it be and how long does it really take for the coolant to get some what dirty. How clean can the system really be after flushing it. My 2000 Accord has clear fluid with nice green color, it is a aluminum block though. I need to add to the Vet but maybe it needs a full flush instead. I hate to flush it then find out a month later the coolant is the same dirty looking no matter what, Thanks

[@ozzstars_cars]

Definitely sounds like your car needs some maintenance.

[@barneythedog977]

@ozzstars_cars almost perfect shape. Runs great. Just needs fluids replaced from time. I scheduled a flush in a few weeks at a local. Shop. Got it topped off and no air in system until then Thanks

[@barneythedog977]

@ozzstars_cars I also have bought the proper green pre 96 m1825 type coolant for shop to use. They are a good shop.

[@RustyGlovebox]

Great job explaining what to look for. That is surprising how much will build up .

[@ozzstars_cars]

Yeah it's a Hoover on wheels. Stay safe Lloyd.

[@CarsExposed]

Great video mate very informative big thumbs up 👍👍👍

[@ozzstars_cars]

Thanks Igor!

[@MsJennaNY]

Thanks so much! Helped me a lot! Having problems keeping my ‘92 LT1 cool. Great video!

[@ozzstars_cars]

Thanks and good luck with the fix.

[@nancycarvalho9538]

Bought another My fifth so getting back to remembering my vettes quirks so to speak, Thanks for the info on LT1

[@ozzstars_cars]

Corvettes can be like thoroughbred race horses at times....frisky.

[@nancycarvalho9538]

@@ozzstars_cars you know it been a while, but kids today don't know how to work on the classics, if not on a computer they lost keep up good work love it

[@paullogan8833]

great info for us corvette owners

[@ozzstars_cars]

Thanks Paul

[@ptfd140]

Another question... My 1994 Corvette is pretty much original. With that said, I have done a flush n fill, new thermostat, cleaned the radiator/condenser area of debris, replaced the temperature sensor, and all the other stuff I see in this video and elsewhere. With that said it still has problems with overheating if I get stuck in traffic on a hot day. Not a problem when I'm moving. But if I'm not travelling by the time the secondary fan comes on it's too late to recover and my engine gets really hot and starts "missing." No problems on cool days. With my friends older Corvette he just replaced his (single wire) temperature sensor switch with a lower temperature one, so his fans come on based on the position of the switch, which activates his fans at a lower temp than stock. That does not work on my 1994. There is no lower temp switch because this is a two-wire sensor and sends a signal to the ECM and the ECM decides when to turn on the fans. Man, I hope that's not too confusing. The older ones are on/off, the newer ones read resistance. I also looked into reprogramming the ECM to turn the fans on at lower temperature. That's a no-go. Without going into details, the 1994 and 1995 model years have some funky computer stuff going on with OBD1 and OBD2 stuff. So I was thinking of going with a "Derale" brand adjustable dual fan controller, here's a link to check it out: derale.com/product-footer/electric-fans/fan-controllers/high-amp-controllers/16789-detail It costs about $125 and you can program the temperature for your fans to come on. My thought is that instead of my fans coming on at @225 and 235 I could use the Derale controller to have my fans come on at 215 and 225. Giving me a little bit of a buffer and keeping my engine safe. Two questions: What do you think of this idea/product? And, if you were to go with this plan where would you install the temperature sensor, 3/8" npt thread-in probe? <

[@ozzstars_cars]

As long as my C4 with the LT1 remains under 235⁰F, I have no concern. Not sure what your misfire is but I would diagnose that first.

[@ptfd140]

@@ozzstars_cars I suppose I should have used the word stutter in place of misfire. My problem is that it's so hot here in the summer that the secondary fan comes on at 235 but the temp is still climbing for a bit. So I'd like to get the fans to come on just a little sooner to head that off. Thank you sir, love your videos!

[@frankkeel8410]

Excellent Video

[@ozzstars_cars]

I appreciate your comment Frank! Thanks

[@Trapshitkalci]

Thanks ! Subscribed ! Just thinking on getting a C4 and for inspecting a a cooling system(radiatior,cooling fans,relays,testing,cleaning) you gave me a lot of good ideas and knowledge.

[@ozzstars_cars]

Good news.

[@louisfabbo1355]

can i take the two screws out of the electrical connecter at the right rear by the head to unplug it to get to the water bypass tube having trouble getting the bypass bolt out i want to disconnect the wiring to make it easyer

[@ozzstars_cars]

Not sure what you are talking about.

[@bugsb70]

Just got a C4 in the same Bright Aqua color. Great info..thanks.

[@ozzstars_cars]

BAM for the win! Enjoy your new ride!

[@donleblanc7223]

Hi Glen; I really like watching your videos on Corvettes. I recently bought a 1993 bright aqua convertible. I had a question about the temperature gauge. I was at car show, and driving there and back I noticed the temperature gauge does not move at all. When I got home the fans kicked on and I got a "Check Gauges" message. Any Idea what is causing this ? Thanks.

[@ozzstars_cars]

The analog gauges in C4's are known to be inaccurate so keep an eye on the digital temperature gauge. What is the temp reading?

[@donleblanc7223]

Hi Glen, the needle does not move from 100

[@ozzstars_cars]

​@donleblanc7223 what is the digital coolant gauge reading?

[@donleblanc7223]

Hi, have not been able to access the digital version yet. I'll check it out.Thanks@@ozzstars_cars

[@donleblanc7223]

Hi Glen; i ran the car today and checked the digital gauges, i got a reading of 74c for the coolant, and 44 for the oil temp. Sorry for the Celsius reading as I'm in Canada.

[@stephendukes]

I cleaned the condenser and radiator carefully with a bottle brush and industrial condenser cleaner. Rinsed and it’s doing well.

[@ozzstars_cars]

Cool!

[@lauromunoz4692]

I have a 94 Corvette just like this one. Thank you for sharing. 😎👍 Sincerely, L. Albert Jackson Munoz

[@ozzstars_cars]

Bright Aqua Metallic were built for about 5 model years. The one in the video is a '93. Can you tell me what is different than a '94 that you have?

[@kmcc0227]

I replaced the temperature sensor for the gsge and for the ecm cooling is great now thanks for your help

[@ozzstars_cars]

Awesome!

[@jhobbs1824]

Thnx for another great video.

[@voschaesthetic6981]

This video was very very helpful. I’m gonna try all the stuff you talked about on my 94 C4

[@ozzstars_cars]

Good idea Vosch

[@rotorblade9508]

one thing is I understand gm recommends green coolant, but the blue coolant has better corrosion protection and some people may use that. But the green coolant has better thermal capacity and can give better cooling efficiency. That’s for the l98, not sure about lt1.

[@stevenrobinson9856]

I drive mines in fall and spring during the cooler months. I dont drive during the summer.

[@ozzstars_cars]

Drive it as much as you can!

[@arewefree]

I have a 85 Corvette , 32,000 miles and runs super good. Like a brand new car. The temperature was running around 220-230 and it was worrisome. I took out the thermostat and it now runs around 170- 205. Fan comes on a bit earlier if I run the AC. I don't run the car in the winter, so why does one need a thermostat? It seems to run so much better at 20 degrees cooler.

[@ozzstars_cars]

The faster the engine warms up usually the emissions are less.

[@barneythedog977]

Great and thorough information!!

[@ozzstars_cars]

Glad the video was helpful Barney.

[@adamsoloman5291]

15.01 LMAO great delivery! Man you'd be a good comedian. You can work with writers you'd be great honestly. Loving the videos btw - super informative. I have a 94' myself.

[@ozzstars_cars]

Haha thanks Adam. I could use a good promoter and p.r. person for open mic night. 😂

[@yasharali2495]

Great video! Great tips. Thanks for responding to the comments.

[@ozzstars_cars]

Thank you

[@Mike-zf4ev]

I just bought a 92 conv. Thanks for the information. Good STuff

[@ozzstars_cars]

You're welcome. Enjoy that C4!

[@garypiont6114]

Thanks for great c4 vids. Especially the sensor location vid.

[@ozzstars_cars]

You're welcome Gary. Thanks for checking them out.

[@DC.]

Thanks man! I learned a lot in this video. Great info.

[@ozzstars_cars]

That's what it's all about! You got it. Thanks -Glen

[@samrothstein9716]

The fans aren’t even programmed to come on until 220. These cars are designed to operate at 220-240, completely normal. Coolant and system pressure raise the boiling point to around 270-275, so no problem being at 220-240.

[@ozzstars_cars]

Over 220 is HOT!

[@skyking1328]

Well, I bought a used 140K mile 1996 C4 ten years ago. Long story short, ended up replacing all components in the cooling system. The plastic radiator was leaking, holding tank and thermostat was gunked up. Chevy designed this motor to run in the 200+ range to burn off hydrocarbons. While rebuilding system , I replaced the thermostat with a standard Chevy 185 degree unit which made the engine run at the old fashion normal temperatures. Running at 225 degrees just seemed stupid as it ruined the plastic components. The only bad price to pay doing this was, the cabin heating system was affected so you don't get much heating in the winter. That's fine with me, because I only run the car in the summer time. Engine runs just fine at the lower temperature with no check engine lights. AC and fans run just fine in the hot desert sun. Following all that, ended up replacing water pump, opti-spark, IAC and removing intake to correct the common rear oil leak on the LT1. After all that, the automatic transmission started slipping and had to have it rebuilt. My C4 is high mileage, runs like new now , but I don't think I could break even selling it at the used car price. It's a real nice looking hot rod for an old guy ! LOL !

[@ozzstars_cars]

The C4 is a bargain sports car. Some people like to put it down but the '92-'96 is the cream of the crop and a bargain to boot. Enjoy your car!

[@bobparrott8130]

Thank U for the great video I have a 91... very good information 👌

[@ozzstars_cars]

Glad it helped

[@SmittySmithsonite]

*Cool* video, Glen! :D Wow, that engine compartment does NOT look like a place I'd want to spend any time in. Things are TIGHT! TWSS ... Looks like that radiator picked up some doubage and a 8-ball ... not that I know what those look like ... but it looked that way. :D Nice ride, brother!

[@ozzstars_cars]

All kinds of paraphenilia hidden in there Smitty.🤘 Fortunetly this car is pretty reliable and I don't have to bust my knuckles much. Take care

[@SmittySmithsonite]

@@ozzstars_cars - Glad to hear! That was in the era where GM still cared about customer service. That's a solid platform right there. These days the bottom line is all GM cares about. Parts made everywhere but the USA by low bidders. I was just reading a multi-page post on a forum about AFM problems on a '15 Sierra. This was a problem in 2007 ... and they're STILL using the same crap parts! Unreal. :( Oh, and my Silverado is down - I lost 3rd and 4th gear! Transmission time, at 103k miles, case in point! Time to get under the hood of a Toyota. Got some headlight assemblies to change, plus the belt, idler, and hydraulic tensioner to swap. I'm prepared to bleed ... :D Have a good one, Glen!

[@ozzstars_cars]

@@SmittySmithsonite you are right about those parts. GM was bailed out of bankruptcy and they must cut every corner they can. The CEOs need that big cheddar! Good luck with the Toyota, may all your nuts and bolts be rust free. Hahaha

[@SmittySmithsonite]

Ozzstar's Cars - It turned into a semi disaster. The tensioner hex rounded off on me, because someone torqued it to 3,420 foot pounds at the factory 14 years ago. I had to file what was left of the hex, place the socket on as far as it would go, then pry against it with a 3 foot prybar, then hit the prybar with big nasty to get the socket to force its way on there. Then I was able to work it out of there with everything I had on my 3/8”ratchet. I had to grind the hex off and weld a nut in its place. Went from a 14 mm hex to a 18 mm hex, but it works! Saved me a trip to Toyota. 😁 My buddies stopped by in their hot rods today. One of them had a Corvette around the same generation as yours I believe. I forgot what he said what year it was. Anyway, he laid a nice patch here. I shot a video for you. The first car is my buddy’s crazy 900 rear wheel horsepower ‘11 Camaro. 😎 kzbin.info/www/bejne/qKvLkqBsmMtjqsU

[@ozzstars_cars]

@@SmittySmithsonite sounds like a fun day man. Wish I was there. 🤘

[@normansmith7806]

Good one Glen !

[@ozzstars_cars]

Thanks Norm, always appreciate you stopping by.

[@kennethwallace3447]

Awesome Info .... Not gotta get to work Thanks!

[@medicmark9683]

Love your corvette videos I got a 1986 what was the best coolant to use on my car

[@ozzstars_cars]

The good old green stuff!👍 Unless somebody put the orange Dexcool garbage in.

[@jimmerriman6920]

How about cooling system thermostat temp change? I've heard that it's a good idea to lower the thermostat temp to maybe 165 degrees F. Your thoughts?

[@ozzstars_cars]

That's a waste of time and money.

[@rossschultheis8098]

Will the car run cooler if you put a 160 degree thermostat? I keep on hearing different things

[@ozzstars_cars]

@@rossschultheis8098 nope. Fix the real problem.

[@josealvearziegler6048]

Gracias muy buen video, yo tengo el C4 1994 hace poco tiempo, consulta donde va el sensor que indica la temperatura en el marcador análogo del tablero ?.. Pregunto porque el marcador análogo del tablero no funciona, gracias saludos.

[@ozzstars_cars]

You're welcome, uhhhm de nada.

[@kelvinbrooks9588]

Nice video!! Cool tips!! Awesome job dude. Thanks a lot!!

[@ozzstars_cars]

Glad you liked it!

[@lashlarue2266]

My 94 has an OBD2 connector with an OBD1 system. Do you know what would be diagnostics mode comparable A & B of the OBD1 compared to my OBD2 connector?

[@ozzstars_cars]

Your car only has OBD 1 technology.

[@lashlarue2266]

@@ozzstars_cars... my problem is that I have the OBD2 16 pin connector. I'd like to be able to identify the 2 comparable diagnostics pins in the in the 16 pin connector to the 12 pin connector. I realize you may not know. Thanks.

[@ozzstars_cars]

@@lashlarue2266 of course I know. In your '94 jump OBD2 connector pins 4 and 12. The codes will be displayed in the digital center screen and you will need to use the TRIP ODO button to scroll through.

[@MattHeere]

I never worried about any of this in the Mustang, but that was probably because it's never that far until a bend in the road here in WPA. The time it takes a Mustang to go around a corner is plenty of time to cool off :)

[@ozzstars_cars]

Haha that's a good point Matt. Glad to see you stop by here. Where have you been hiding?

[@MattHeere]

@@ozzstars_cars Changes at work got me insanely busy. Hoping to get back on the circuit here for the annual Christmas light stuff at least!

[@murrayhale496]

Excellent video Thank you!!

[@ozzstars_cars]

You're welcome Murray! -Glen

[@redlinedetection]

Great video 👍and thanks for the Redline shoutout!

[@ozzstars_cars]

Thank you!

[@youngestson6537]

Very informative. New subber.

[@ozzstars_cars]

Thanks

[@taquitopicante5863]

Dude! Excellent video, sir. I have a '96 LT4, 6spd., live is AZ, and find that mine runs at about 205*-215* in town. I was wondering if you had experience with that product "water wetter" for helping to reduce cooling temps? Cheers.

[@ozzstars_cars]

Yes. I have actually discussed the product with one of the engineers. Seems the older the car the better it works. Do your research before using it. Did you clean the radiator yet?

[@taquitopicante5863]

@@ozzstars_cars Yes. I replaced my radiator about a year ago due to a leak in it. Put in a 3-core replacement. Was hoping that fix alone would drop temps. Maybe insufficient burping? Thanks for the reply.

[@sebbonxxsebbon6824]

Callaway sold twin turbo cars, do they use a larger or better radiator?

[@ozzstars_cars]

I've seen a couple of Callaway C4's and I recall the cooling system being upgraded.

[@robertg8875]

Ozz is there a video for a c4 smog pump removal and what replacement bracket to use

[@ozzstars_cars]

Are you referring to the air pump located under the left headlamp in the engine compartment?

[@robertg8875]

@@ozzstars_cars no this is above the alternator and a aftermarket bracket

[@JAYY_JAYY]

Hopefully someone can respond I own a. 1986 Indy pace car edition . The battery was dead I jump start and Just let it idle about 15-20 minutes. I get in car to look at gauges and See the temp at 260 degrees . I turn off engine and leave key in to monitor temp it went up to 265 before going back down as the car was off . Is there any way to confirm if I damaged engine ? Plan to change thermostat first .

[@ozzstars_cars]

@JAYY_JAYY make sure the cooling feeling are working properly. Test the fuse and relays.

[@jeffreyniles6575]

Excellent info

[@luthiervandros]

Great color!

[@ozzstars_cars]

Agree! Bright Aqua Metallic

[@ricksgarage8069]

I replaced the radiator with a dewitts, installed a 160 thermostat, and sent the ecm to Wong's performance in Vancouver, WA where they reprogrammed the cooling fan temps on my '94. On a hot day in traffic, it never exceeds 190. BTW, Glenn, are you from PA?

[@ozzstars_cars]

Wow Rick you went all out. I assume the engine isn't stock and put out some extra horses?

[@ricksgarage8069]

@@ozzstars_cars Everything else is stock.

[@andrewalvey7821]

Would it be rude to ask how much that ran you? I’d love to drive my C4 in stop and go traffic and not worry about coolant temp.

[@ricksgarage8069]

@@andrewalvey7821 Sorry it took so long to reply. The Dewitts radiator for my 94 manual was $570 and the Dewitts radiator for my '93 automatic was $600 from Speedway Motors. (free shipping). The price has gone up since I bought them. It cost $100 each plus shipping to have the control module reprogrammed to lower the fan-on temps from Wong's Performance Engineering of Vancouver, WA. I recommend them. Then there was the thermostat and new coolant. I did all the work so there was no labor costs. If you plan on doing the job yourself, let me know and I will walk you through the process.

[@ricksgarage8069]

@@Tamvalleyracing kzbin.info/www/bejne/bnyaeniOrKZ4ms0

[@ronjerrett3962]

Very good info.....thanks!

[@ozzstars_cars]

You got it Ron!

[@mrdubois4547]

Thank you very much I will check all of that after the winter! But I have a 1990 l98, are those systems different than the lt1? Plus is it possible the 1990 does not have digital gauges? I checked all the switches and there is none. My analog temp goes all the way almost to the maximum and stays there unless I'm on the highways temp is perfect. And when the temp is hot it smells a little bit of coolant, but no leaks.

[@ozzstars_cars]

Scroll through the electronic gauges using the buttons on the dashboard to the right of the steering wheel.

[@larsz5224]

mr dubois, here is a reply I had to someone else earlier, thought you would like this info. First, Glen, good video, good info. I owned an 88 vette for 30 years. Setup included L98 auto, electric fan and electric optional pusher fan. I changed the thermostat to 180, replaced the 235 temperature switch in the side of the block that turns on the pusher fan to a 200 and added a jumper wire from the pusher fan relay to the main fan relay. That way both fans turned on at 200. Highway temp rarely over 180. In town and parades never over 205. The factory design just left too little buffer between operating temps around 235 to cracking the aluminum heads at 260. Hope this is helpful.

[@mrdubois4547]

@@larsz5224 Thank you so much!

[@kmcc0227]

Yes fans work with clip just had intake manifold gaskets done no leaks I'm thinking relay ? Fans go on with ac on

[@ozzstars_cars]

Did you find the problem?

[@rossschultheis8098]

What kind of optispark would you recommend?

[@ozzstars_cars]

Petris

[@rossschultheis8098]

@@ozzstars_cars yea i herd about that company i still dont know if mine is bad or not has less then 300 miles on it. Could a coolant sensor still be bad if you don’t have a engine light on ?

[@BackCountryWrenching]

why are the fans coming on so hot ? I have mine set to come on low at 196 and high at 205

[@ozzstars_cars]

Corvettes like the heat, especially the C4 generation. I'm not sure why it's engineered liked that but believe it's due to the reverse cooling system the LT1 has.

[@jamesflames9930]

They come on Hot because Federal Regulations are always changing for Gas emisions so GM set the fans to turn on at a higher temp because the hotter the less bad gas emisions your cars putting out.You can tune it to turn on at a lower temp but as time gos by OBD1s are getting harder to find a tuner.

[@billdurant2007]

is there a bleeder valve on the 89 vette? if so where is it, thanks

[@ozzstars_cars]

I don't believe there is because the engine in an '89 has a different cooling system than the LT1.

[@donleblanc7223]

Thank you for this informative video, I will soon be in the market for a 95/96 and this info is most helpful. May I ask the color ? it looks like bright aqua, (which I am looking for) . I had a 94 that unfortunatly had a spark plug wire came loose and hit a metal shroud. Long story short, 2K $ later it zapped the electrical / timing. lesson learned.

[@ozzstars_cars]

This is a '93 paint color is Bright Aqua Metallic. Electrical shorts are no fun.

[@davidgarrett9846]

Thank you for your information 🙏

[@ozzstars_cars]

You're welcome David

[@georgehgordy1690]

reverse cooling = forward overheating.. 226 degrees is when the fans kick on.. GM did this because it helped the engine pass emissions regulations.. Purchase a spare ECM have mated to your VIN and have it re-programmed so the fans kick on at 180 degrees.. When it comes time for your yearly emissions testing install your original PCM ( takes about 5 minutes ) after you pass reinstall your replacement ECM.. your motor will thank you for it

[@ronnierenner3184]

have you ever cut any of the housing out inthe front part

[@ozzstars_cars]

No but it is tempting.

[@ronnierenner3184]

@@ozzstars_cars i really wanna do it

[@ozzstars_cars]

@@ronnierenner3184 if it's an old beater and never has a chance to be NCRS judged then go for it.

[@robertg8875]

Any chance of a heater core fix on a 90 c4

[@ozzstars_cars]

If I had one come in I would take the 8 hours to film and edit it. Most don't drive there Vettes in the winter around here and bypass the heater core. Fast and cheap. 🤷‍♂️

[@robertg8875]

@@ozzstars_cars any disgrace in putting a by pass so I can at least drive the car ?

[@ozzstars_cars]

@Jeff Spicolli Mr. Hand said so. 😁👍

[@RidgebacksC]

I have a 94 lt1. Been sitting almost two years. Should I do a complete flush of the fluids?

[@ozzstars_cars]

@@RidgebacksC I think you know the answer. 👍

[@dougcoleburn1579]

Really great video. So I'm looking at a 94 with 85,000 miles. Very original car. What type of service life can one expect out of the opti spark. And water pump? Is better to just go ahead and replace water pump with a AC delco pump and be done?

[@ozzstars_cars]

If ain't broke why fix it? A visual inspection is necessary to make sure no coolant is leaking. If there is a leak then obviously it needs attention asap. That mileage isn't scary if things are well maintened.

[@dougcoleburn1579]

@@ozzstars_cars thanks! Going to change all the fluids and filters and go from there. I know these C4 can have some quirks and things to fix but it’s such a great car with the six speed for a $7500 entry fee! Not many cars with this type of cost per fun ratio. And I love working on cars so it will be fun.

[@ozzstars_cars]

💯👍

[@BlacKnightRising]

what an awesome color

[@ozzstars_cars]

Agree. Bright Aqua Metallic, we call the car BAM.

[@andrewchavez7185]

Sir I need some help. I’m not very mechanical and I recently bought an 88 vette and I turned the the car on and it’s saying low coolant, but I checked the coolant and it’s full. When I turn the car on and flip the switch to check the oil and coolant temp it says low, is this normal?

[@ozzstars_cars]

Hard to diagnose a problem like that over the internet. Wish I could help, sorry.

[@jbotnick5361]

Much appreciated brother

[@ozzstars_cars]

👍J

[@ScreamingEagleFTW]

are the LT4 head gaskets as tough as the LT1? Thanks

[@ozzstars_cars]

Yes.

[@ScreamingEagleFTW]

@@ozzstars_cars thanks does the LT4 have any disadvantages over the LT1?

[@ozzstars_cars]

@@ScreamingEagleFTW yes, 30 horsepower

[@ptfd140]

The paper clip trick did not work for me. Upon closer scrutiny I recognize that you have an OBD-1, while my 1994 has and OBD-2. Any workarounds? Another thought... I have read or been told that even though I have an OBD-2 plug on my 1994 C4, it is actually still only OBD-1 scanner compatible. Any thoughts?

[@ozzstars_cars]

Of course I know how to pull codes on a '94 OBD1, with a scan tool but I'll share my knowledge with you. On your obd2 connector jump pin 12 to pin 4 OR 5, they are both grounds. Then you will see the codes on the digital center dash screen. Scroll through the different modules using the buttons to the right of the steering wheel that says gauges, trip odo, eng/met. 👍