1971 Chevelle SS454 OVERHEATING at IDLE fix???

[@rogjackson]

I agree. Your corrections were not a failure. Information is power. Even negative information is power. If something doesn't work, you want to know it (so that you can continue to make helpful corrections and advancements while studying the problem). Cool video! Dealing with a similar situation on a big block 70 Elky right now. Everything is fine and dandy while driving around. Not fine and dandy in stopped traffic on a warm or hot day. Not sure if it is an airflow or waterflow problem yet.

[@SS454LS6]

Please let us know what you find. Thanks

[@billsmith2212]

Just a general tip . Get the car hot and shut it off . Move your hand over the front and back of the radiator core . If you find any cold areas , usually in the center , the tubes in the core are clogged . You can do this running with an infra red thermometer if you get a clean shot at the core . An thermal imaging camera will also work . There are also dual and triple flow radiators .

[@malibuStroker]

I had the same issue with mine. After going thru a flex fan, heavy duty clutch fan I ended up having to switch to an aluminum shroud and dual derale electric fans. Now it stays cool here in Texas and usually only runs one fan and occasionally kicks on the second. I hate electric fans and they’re expensive, but cheaper than a new engine. Ugh. Good luck and thanks for the video.

[@SS454LS6]

I hope my issues don't turn into another money pit.

[@kenf2662]

@@SS454LS6 Get a 19 inch 7 blade clutch fan

[@markturon4171]

Use soft water. Distilled water is not good.

[@deanerbes5725]

Try connecting your vacuum advance to manifold vacuum instead of ported if not already. Ported is for emissions. You may need to adjust your idle speed down. Just a thought.

[@65sohc]

As you noted the blades on your present fan don't have all that much pitch and don't take a very big bite out of the air. I think a more aggressive fan with clutch will solve your problem. Basically the way the factory did things back then. I doubt that any more tweaking of the shroud will make a difference. There are plenty of cars running around with no shroud at all that don't overheat, not that that's the correct way to do it. Did you happen to watch the Engine Masters episode on fans? They tested virtually every configuration and got very interesting results. On another note, how is your Fitech running? I don't know if you are aware but there is a Chrysler engineer on the Fitech tuning forum who, for a nominal fee, will analyze your datalog and write you a custom program. He'll continue refining it till it meets your satisfaction. He completely transformed my GTO. He is the real deal. He is one of the engineers in charge of powertrain calibration on the Hellcat and Demon, among other projects.

[@daveburn71]

You have a large gap around the sides of the radiator. Feel this area with the hood closed. You'll notice that it is like a blow dryer. The hot air that is in the engine compartment comes around the front of the radiator if it's not blocked. This is another factor when sitting or slow moving traffic. 2nd thing is that you have too large of a gap between the fan blade tips to the shroud circumference. That gap should be 1/2 to 1 inch max.

[@kenf2662]

Your right what changed the car went from stock to hot, I remember back in the 70s driving my nova in Vegas at a 112 in July not a problem never over heated.. What changed,. There is two big factors first is the engine temp "CAM" , second is the under the hood temp "HEADERS". combine the two spells too HOT ! and if you have a intake close to all that you will start to run rich start knocking and wont stay running. Get a 19 inch 7 blade clutch fan

[@v8vega383]

I've got an 18.5 inch Flexalite flexfan if you want to try it before you spend any money. If it works I'll take $40 for it, I believe they're almost $100 new. It pulls a ton of air and worked really well for my ride. I decided to go with a Derale dual electric fans for street/strip use so I can cool down quicker between rounds. I'm in Sherwood Park, message me if you'd like to try it.

[@SS454LS6]

Wow that's awesome! I am currently trying to source a couple of specific parts, but if it doesn't pan out I'll keep that in mind. Thanks!

[@warpigolet]

Love the valve covers. But the "hot air induction", does not help! We all did it back in the day. Did you say LS-6? Don't think so! LS-5 with hydraulic lifters? You are making good points on this, expiration of overheating. Press on!

[@SS454LS6]

It's an LS5

[@colinrosenthal4296]

Bigger clutch fam will likely solve your issues and also if you can do a bit more to deal up the edge gaps on the shroud. I have solved a similar problem by doing so before.

[@SS454LS6]

I just need to find a fan to my liking, and one that is available.

[@colinrosenthal4296]

SS454LS6 and one that’s in Canada.

[@applianceguy613]

We had a 1975 Suburban 454 5/8 ton, could not cool it off towing a 23' sailboat. The water jacket was too thin.

[@showmethedammovie]

Gaps next to the radiator is a problem. Air will actually go around the radiator if possible. Get the correct shroud and radiator. Shrouds tend to be not centered as people believe. You still can use a bigger fan with that shroud. The gaps from the shroud to blade should be small as possible. Bigger fan more aggressive pitch. But pitch takes away hp. Make sure shroud is flush with radiator, no gaps... See you did that. Higher flow water pump. New thermostat. Also add water wetter. You can do a before and after. Me and lots of people have results from it. I buy it for presents. Lol.

[@65sohc]

I'm going through a similar situation with my 65 GTO with 406 sbc. I also live in central California where it got up to 111 last week. The guy who tuned my Fitech suggested a high flow water pump so I ordered a Flowkooler. Should have it installed next week.

[@SS454LS6]

Let us know if it makes any difference.

[@mikes9939]

Pontiac's are a special problem because of their water pump design. The rubber pump seals must fit tightly and the pump must be a good one they fits in there closely. If the motor mounts sag then the fan is not centered in the shroud and air is lost around the blades.

[@mikes9939]

Sorry I just noticed that you have a SBC not a Pontiac engine. A big 4 row would probably help you out too. I have a 76 Corvette with a stout 350 and I added a fourth row to the original copper brass radiator. It stays on 180 degree like a rock. Corvettes are tougher because all the air comes up from the bottom so shroud seals and the spoiler are very important.

[@paulthompson8480]

hi Get the correct radiator ,fan diameter and correct fan shroud diameter and fan spacing . ALL OF THESE WORK AS A PACKAGE . Depending on model of vehicle but most GM cars have optional h/duty cooling packages available .

[@cidertom5140]

Does this have auto choke or manual and does the car have a manual gearbox? I noticed how high the idle was when you did the paper test. You should only used distilled for batteries. I use tap water for radiators in my Peugeot and have done with my other cars that I’ve had.

[@SS454LS6]

its EFI. The idle is normal for a BBC. No way I'd use tap water in a radiator. Too many impurities that reduce it's boiling point.

[@cidertom5140]

@@SS454LS6 there’s the problem too higher idle.Reducing a boiling point has to be good. No overheating.

[@cidertom5140]

Can’t be EFI. Your car is carburettor.

[@SS454LS6]

@@cidertom5140 I'm quite certain I know what's on my car.

[@jefferysteffens8475]

P.S……Ditch your water pump if it’s an aftermarket POS and find an original water pump. Get it rebuilt if needed. Please remember….these cars and their components were designed by engineers who actually knew what they were doing. Everything worked in unison.

[@mikepierce9851]

What did u do to fix the overheating. Ive got the same car and motor

[@SS454LS6]

I couldn't get parts in before the weather got super cold. I do plan on changing the rad cap to see if that fixes it. I've seen that work before.

[@141runn]

looks like you have a reverse rotation fan on it

[@milesbaker7499]

The blade to shroud gap is the big problem. You want as small a gap between blade and shroud as possible. I stay around 1/2" max. If possible, you want the blades a little out of the shroud too, front to back. Get a better shroud. That's your only problem. 1.5" gap, you've basically got no shroud. Your fan size doesn't really matter for idle cooling. Think how little fuel you're burning, maybe making a few dozen HP of heat. Any 18" fan design should be able to move enough air to lose that amount of heat. Same with radiator size. If you're cooling at speed, your radiator is moving a lot more than those few dozen HP of heat. Idle overheat problems are virtually always airflow, and that's virtually always shroud problems. The rest of the time it's a water pump that doesn't move water at idle. It makes me laugh to hear people say they bought a huge aluminum radiator and expensive electric fans because of idle overheat. You literally are only moving a few dozen HP. Anybody should be able to cool a 1000hp motor at idle with cheap parts. You only need the high dollar stuff when you actually have the foot down and it's burning huge volumes of fuel.

[@SS454LS6]

I think a larger fan would definitely help.

[@milesbaker7499]

@@SS454LS6 Derale make a twenty inch for like forty bucks. Gonna be a lot of load at speed. Might want that clutch.

[@75zl1]

@@SS454LS6 I am going to agree with this. That 68 I bought had the same exact problem. It had a 16 inch fan in a 19.5" shroud. I held a paper towel up to the fan shroud near the fan and it would suck it in rather than blow it toward the engine. I had a spare 18 inch clutch fan from when I went to electric on my 75 camaro and threw it on. It now has a difficult time getting to 185! It sits right at 180 all the time now. Before idling would go to 230. EDIT: to add, before it would hold a paper to the radiator but I couldn't feel the air moving at the radiator. After the clutch fan(even without it engaged) it will suck it to the grill now.

[@fredmartin1626]

If you use a clutch fan the blades must be 50% out on the back of the shroud to cause a good draft. Check out some OEM fan setups even Chevelle's they all came from the factory that way.

[@SS454LS6]

I've heard this. Even though the performance of the fan seems fine, I strongly believe the noise issue is because of the shroud. Maybe the noise is better with a 50/50 in and out, but I can't adjust the depth with this clutch and shroud.

[@fredmartin1626]

@@SS454LS6 looks like you have a small block shroud, you need to get a BB.

[@mikes9939]

I have had a few big block Chevelles in my life dating back to 1972 when I bought a used 1970 LS 6 car for $2400 off a dealers lot when I lived in Fla. I have owned a few since then but one thing I never had a problem with was overheating. That may sound unbelievable but remember that if you use factory parts correctly then you will not have a problem. Remember that the factory could not sell cars that overheated, customers would complain. So with that in mind then if you mimick what the factory did then you should be OK. I see lots of things wrong with your car right away. The big block cars used 4 row brass and copper radiators and the clutch fan with 7 blades. With a 180 degree thermostat. Don't fall for the trap of using a 160 on a street car. The water has to stay in the block long enough to absorb the heat. Get rid of the direct mounted fan and use the factory clutch. That fan is way too small , doesn't even fill up the opening, more aftermarket junk. Avoid the cheap Chinese replacements, get a Hayden designed for these cars. Get the right fan blades not some aftermarket junk that doesn't fit the shroud as it should. They need to be the right diameter and make sure the shroud is correct. That radiator is way too small, it should fill up the opening in the radiator support. Also you do not need any goofy aftermarket water pump. I have always used regular long water pumps even in hot Florida with never any problem. Always remember that the factory did not have any issues so copy what they did. It works. I have had some pretty potent engines in cars that I drove regularly on the street using normal stuff and overheating was my last thing to worry about. You have some bad stuff on your car. Do it like GM made it. The previous owner left a lot of junk for you to do away with and get the right stuff. Also use normal timing figures for your engine unless you have some radical engine. !8 degrees initial and 38 total for an engine with a big cam is enough without vacuum advance. Don't put a electric front mounted fan on. Fans like to draw not push and they just block the airflow if they are in front. You will not need it once you get things sorted out.

[@SS454LS6]

I have ordered some parts and will make a video to see how they do.

[@kenf2662]

Your right what changed the car went from stock to hot, I remember back in the 70s driving my nova in Vegas at a 112 in July not a problem never over heated.. What changed,. There is two big factors first is the engine temp "CAM" , second is the under the hood temp "HEADERS". combine the two spells too HOT ! and if you have a intake close to all that you will start to run rich start knocking and wont stay running.

[@cuzz63]

His motor is not longer like it came from the factory...having the thermostat open at 160 will make no difference on whether the water/coolant removes heat from the engine....all that does is determine what temp the thermostat opens. With that said there are things that the factory got right and thats a high flow clutch fan will move alot more air that a flex fan or electric fans and a larger rad as well as good shrouding will make a difference.

[@Mike-lz7ec]

The fan is not big enough. To much space between the blades and the fan shroud. 🛠️

[@v8vega383]

👍

[@ProsperousThoughts]

Could possibly be oil pump and pickup

[@SS454LS6]

Explain please

[@rhodycars6058]

Any follow up?

[@SS454LS6]

I have the parts! I just need the weather to warm up so I can do a valid test. No point testing coolant temps when it's still cold enough to snow

[@rhodycars6058]

@@SS454LS6 thanks for the heads up. Trying to figure out some percolating issues in my camaro bbc

[@SS454LS6]

@@rhodycars6058 Cooling issues can sometimes be difficult to diagnose. I look forward to seeing if the new parts solve my issues this year.

[@jefferysteffens8475]

Initially……you have the wrong fan. A real LS6 454 had a special fan, even different than the 772 fan used on Hi-Perf. Big blocks. Do you have a fan clutch? Anyone who has a Chevelle who doesn’t know if their fan is on possibly on backwards has no business owning one. Get the proper fan…get the proper fan clutch get the proper fan shroud and make sure you have the rubber flaps attached to your inner fender wells.

[@rdspix]

Add electric fan

[@jm1551701]

Fan clutch'