JEEP CHEROKEE: 7 DEADLIEST SINS OF AN OVERHEATING XJ!!

We walk through the 7 most popular reasons your XJ is overheating. We compare parts and explain each deadly sin of the cooling system. Radiator, Tstat, Tstat Housing, Fan Clutch, Radiator Cap, Lower Radiator Hose and Water Pump. Plus more information that can help you with the frustrations of your overheating issues.

[@lorenskia]

31 years of auto and diesel. One of the best kept secrets to cleaning radiators is Cascade. Yes, that Cascade. Powder or liquid works. Irrespective of the volume of your radiator and cooling system, a mixture of 1 cup Cascade dissolved into each 1 gallon of water will do the best job. This works wonders on the largest of diesel radiators, as well as any automobile radiator. Fill your coolant system with the mixture, and turn the heater on to ensure your cleaning everything. Start and run the engine to operating temperature. Some prefer to keep the rpm to an elevated level, but if you have time, the engine's normal idle works fine. Allow the engine to run for 45-60 minutes. Drain the cooling system completely. Refill with water and run for 15 minutes. Drain again and flush all water from the cooling system. If you wish to look into the radiator, you're in for a treat. I will be clean as the day it was made. Refill the cooling system with the recommended antifreeze/coolant and water mixture. Not only will you have cleaned and descaled your radiator, but also your entire engine. The mess that you flush out will amaze you. One would be hard pressed to find an auto dealership or diesel shop that does not have random $5 boxes or jugs of Cascade sitting atop tens of thousands of dollars of toolboxes and tools. It's literally the best thing since sliced bread.

[@edwardl.990]

I have personally done this in diesel trucks and gas engines too. It works very well.

[@keithlucas6260]

Matt's Offroad Recovery channel addresses this....the worst pumps are the supposed hi-performance pumps with the plastic impeller that breaks down.....he went back to the stock one.

[@VT5874]

Do you know what video he talked about that in? He did mention it in one video I’ve seen. He said it was really good, but not for his application because he runs his engine at 5000 rps so frequently. The impellers are aluminum now also, so i wonder if that changes things

[@amyrinearson6847]

Great video! I have to say, nice job dedicateIng each sin. I found it funny.

[@jeremykopp9859]

Thank you for watching! I appreciate the comments.

[@buckadillafilms]

Great video, and a great channel! I really like your presentational style and I truly appreciate the inside info on the XJ. Sincerely, a new '99 XJ Limited owner

[@jeremykopp9859]

Thank you so much Zane! I appreciate you watching. I will have more videos posted very soon!

[@morganheberling]

99 XJ SPORT! WHAT U JEEP BRO???P!!!

[@grenobel]

I went with a ZJ fan clutch for about a month. The noise didn't bother me so much as the significant drop in fuel mileage. With the ZJ fan clutch being engaged nearly constantly it produces a significant drag on the engine. Mine dropped my mileage by 2.5 mpg, so I swapped it out for a new XJ fan clutch and it works only when it's supposed to, keeping things at proper temp without the fuel mileage hit.

[@richtyler1353]

Great job very informative thank you

[@jeremykopp9859]

Thank you for watching!

[@Dd-bk7rr]

I think doing the thermostat boiling test is brilliant. Thanks for the tip

[@dandahermitseals5582]

That's and old basic procedure for testing thermostats. I'm knocking on 80 years old and remember this from. My childhood. Dandahermit

[@johncampaniello9658]

Thank U sir great video very informative and to the point. I hope to see more of your videos .

[@jeremykopp9859]

Thank you very much for watching! I will be posting more videos very soon.

[@jackbower8671]

Awesome video!

[@jeremykopp9859]

Thank you very much!

[@aarondavis6014]

Much appreciated, thanks.

[@tinkerberns5216]

Thank you very informative

[@CubeComputerChannel]

10:25 The fan clutch with the threaded end is actually not for the 4.0L ZJ. The "ZJ" fan clutch in your video appears to be for the WJ as the 4.0 on those have threaded shafts. The clutch body is identical, though the 4.0L ZJ fan clutch has the same shaft with the 4 mounting holes as the XJ clutch. I think you had the correct part number, just the wrong fan clutch in the box. As for lower radiator hoses, I just transfer the spring from the old one to the new one.

[@thefaisal13]

A really informative detailed video, many thanks. Any thoughts on mishimoto fans on the XJ?

[@jeremykopp9859]

Thank you very much and I appreciate you watching! I dont have an opinion either way on the fans. I have only used the Mishimoto radiator. Very good product though.

[@thruitallauto2538]

Good sermon

[@stevenm7566]

Very thorough, learned some things. Did not know about the air hole in the T-stat. When you say it should be at 12:00... you are saying to the rear of the rig while you are standing in front? Keep up the good work! Thanks

[@jeremykopp9859]

Thank you so much for watching my friend! I am happy to hear that you are learning some things and getting something out of my videos. So if you are replacing the T Stat, the hole should be placed at the top when installing it. Make sure it is not to the bottom or the side or it will be submerged in fluid the entire time and not able to release air properly. Thanks for the question.

[@turbolag5107]

Nicely done. I'm trying to chase down an overheating issue in my own 2000 XJ and I don't think it's the cracked head problem but what happens is it'll get up the temperature just fine it will idle just fine but it's like air is continuously getting in the system somehow and it'll be just fine but then after a few days or a few hours or whatever I'll shut it off and then all of a sudden it'll start boiling over. Admittedly I haven't done anything except a garden hose flush but I intend on changing out lots of parts

[@jeremykopp9859]

Thank you for watching. It sounds like you have limited flow through the radiator and it is causing air gaps which are causing delayed overheating. I would recommend you flush that radiator very aggressively. My suggestion would be to take the radiator completely out and run the hose through the inlet and flush it out.

[@turbolag5107]

@@jeremykopp9859 you're probably right and I'm looking into new radiators. Now I did do a quick flush following bleep and jeeps video and I remember when I went to flush the heater core that thing was pretty damn clogged but I did eventually get it to run clear. I'm probably just going to drop a new radiator into it since I can get them off of RockAuto for about a hundred bucks. I'm thinking the system is probably just absolutely filthy and things are just clogged up.

[@danielshy2638]

Water pump

[@moabwheeling]

Great video again !! I love your caption descriptions of each part that was epic Lol .. How do you like your Mishimoto radiator ? I've been looking into a better radiator to replace the factory style radiator in my 4.0 L TJ . My TJ stays at between 207 to 213 degrees in the summer time ,but when on the trail it will get up to about 215 degrees. Thinking I may add an external electric fan to the front of my radiator controlled by me via a switch to help with the temps while off road . Until next time take care and be safe . P.S . How are you liking our snowy weather ? I actually love it myself Ha Ha .

[@jeremykopp9859]

Hello! Thank you so much for watching and I really appreciate all the comments! I love the Mishimoto radiator! It has been excellent so far. It is a lot bigger than the stock radiator and really conducts heat well. I would definitely recommend putting in a secondary electric fan. I have mine connected to a toggle switch so I can control it as well. I love the ability to be able to turn it on or off based on temp. I love this weather! The main thumbnail on this video is from Monday up at Guardsman. Just got back from hiking up Millcreek Canyon for a little 6 mile hike in the snow. It’s my muse!

[@deadspeed6679]

Part number for the crown T stat housing ?

[@MaquinasDePalomitas]

Nice vid!! Been watching it every day for the past week. I’m gonna order a Mishimoto radiator tomorrow, been procrastinating cause I’ve read a few bad reviews (for the price I was expecting nothing but praise). How has it turned out for you??? My xj’s pretty rusted inside the block, plan on putting an inline coolant filter. Hey man, really helpful vid, I was blown away with the lower radiator hose spring deal, I have extreme OCD when it comes to cars and never had it crossed my mind to test the thermostat first, awesome!!

[@Dd-bk7rr]

I have a Nissan patrol and made the mistake of using water instead of collant for a year. The resovoir ended up silted with rust sand. Then I changed to coolant and changed it about a year later. The resovoir is since clean and there is no rust. I would suggest that you change to coolant for a couple of months. Then switch radiator and put fresh coolant and you should be good. I use oem collant and some have a oil content. If you can do a engine flush (pressure water through the system) that should clean out the system and ensure you are good

[@Dd-bk7rr]

Change the thermostat

[@MaquinasDePalomitas]

@@Dd-bk7rr This video is like the over heating bible, learned a lot, and thank you very much for these extra tips!!! I’m gonna change my thermostat, borrow my buddys’ pressure washer and give it a good clean while I have that extra access. Once again, thanks man!!!

[@Dd-bk7rr]

You should do flush followed by 2 coolant changes. Radiator change only after 1 coolant change. Ensure that you remove the thermostat during the flush. The rust sand may corrode the water pump and some other parts like oil cooler or aluminum engine covers or other metal surfaces so if possible open the engine and inspect. The most dangerous thing to a engine is using water instead of coolant. You will know that the engine is getting damaged if resorvoir is full of rust sand.

[@MaquinasDePalomitas]

@@Dd-bk7rr Oh man, I’m guilty of not using antifreeze, when I removed the wp and t stat housing I just noticed a brownish color. When I replaced the rear freeze plug, the one covered by the trans, I did notice lots of sludge, I removed what I could with my finger and just left the rest there. Thing is that my old radiator is busted (when I was removing one of those e fans attached with wire ties). I”m gonna try to rig something up, maybe a bucket on the lower rad hose picking up water, or tie the in/out hoses together.

[@lessgrep]

About carbon build up. I may be wrong, but with some types of antifreeze, like ethylene-glycol one, white stuff inside radiator is actually a properly working thing and it is designed to be that way. Since its one of ways to defend insides of radiator from corrosion, on some types of antifreeze(G12+ specifically) you wont see such a thing, because rust inhibitor is working differently.

[@kellyddanaher]

the stuff is called galvanitc corrosion. or elelictrlsis very bad for cooling system

[@brendonmccarthy8233]

Well done. Had to put it on 2x. But thats just me.

[@jeremykopp9859]

Thank you very much! I appreciate you watching!

[@dandahermitseals5582]

It's not a spring --its a wire spiral reinforcing core and it doesn't actuate anything. It simply reinforces the hose's shape.

[@dealinwithit1]

Do you have part # for lower radiator hose with spring I couldn’t find it on Napa website

[@varoplazer]

Great video buddy do you have a part number on that thermostat housing?

[@jeremykopp9859]

Let me see what I can find for you.

[@vadiesel98]

@@jeremykopp9859 Any luck on that part number? I'm having a hard time finding it as well. Thanks. Just ordered a Mishimoto Rad based on your videos.

[@steventsunami9506]

I anointed my radiator fluid and crammed rosary beads into my airbox, yet still, it runs a little hot.

[@mortenjohansen4120]

Where can I get a Mishimoto t-stat with vent?

[@flutetubamorg]

I don't know if I would soak any part of my engine components in acetic acid. Acids are great for dissolving metal and calcium, not so good at flushing coolant systems. I guess MAYBE if your system as calcium buildup, but if using DI water and coolant, that shouldn't be the case.

[@hectorhuerta6436]

Where can I get the hi flow Houseing at ??

[@jorgerogado9873]

Hello. you could get the reference the house s-stat air high flow system. thanks

[@jeremykopp9859]

Thanks

[@gentilejoshsaved1646]

Mine does not have a cap. It has a tight fitting non pressure release cap.

[@Dd-bk7rr]

How does a thermostat air vent make a difference if the valve opens during operation wouldn't the air ultimately reach the highest point of the cooling system? I would think that in a couple of days the air would finally bubble to the top and get into the resorvoir bottle....

[@MrMrsregor]

yes, probably. but the air vent is there to make the air burp out faster and easier

[@Andy-zr8fi]

Mine took a dump on mountain pass 12 below o blew head gasket

[@albertom.juarez6876]

Where can I get the hose with the spring?

[@jeremykopp9859]

Hello Alberto! Thanks for watching my video. When I first uploaded this video I was able to get this hose from Summit Racing. It seems these hoses are very difficult to find now. I actually put a Summit Racing hose less spring in my 2000 XJ and I have not had any issues. I would recommend just putting in a standard hose at this point. The spring hose is beneficial when your system is running very hot as it softens the rubber on all the hoses and the lower hose is succeptible to collapsing. However, if your system isnt overheating and getting to hot, this shouldnt be a problem. Please let me know if you have any other questions. I am happy to help.

[@ha9535]

Hi mate , been living in Western Australia where the temperature rises to 40 to 45 degrees Celsius. I had few xj in the past ,still have 2001 one with 200000 km very strong car but its overheating with both fan running going uphill or on the beach where temperature is 30 degrees with ac off. In the past I had 1996 sport xj with 128000 km. Overheating issues same like the one that I have. I changed waterpump, thermostat, radiator hoses ,fan clutch and radiator aluminium one after market that was still overheating. So I did headgasket test ,there was no issues with that aswel. I took to the jeep especiallist they couldn't figure out or what causes overheating problem so I sold it. So my 2001 xj with same problem, but I haven't started spending on the car ,I don't want to spend on the car before I find out what is exactly causing the car to overheat. U have done a good ,went through explaining all the things that causes overheating issues. So what do u suggest for me to start with. I will appreciate ur help. Thanks Amir Australia

[@jeremykopp9859]

Thank you so much for watching and the comment. Sounds like you have been through the ringer with overheating issues. There are a couple other things that could cause overheating that you didn’t mention. I know you tested for a head gasket but, you could possibly have a cracked head. Often times the head gasket test will prove negative when you have a cracked head. Another issue with these Jeep’s is, the transmission draws a lot of heat and often times demands more cooling to the transmission and starving the engine of its needed cooling. Increasing the size of the transmission lines from the radiator to transmission is a good solution. If you ask me, the key things when buying a XJ is.. first, check which head is in the Jeep(Very important). Check for any leaks, identify which tstat is installed. After that, mods would be, flush whole system very thoroughly. Replace cap, replace lower radiator hose with spring, use 195 Tstat and make sure it is opening correctly. Then go from there.

[@ha9535]

@@jeremykopp9859 Thanks mate for the info,do I need to upgrade transmission oil cooler. Thsnks

[@stumoo4744]

You might try checking the 8th deadly sin… the harmonic balancer.

[@boneheded2819]

Stu Moos suggestion is a good one. The harmonic balancer can separate since it is made in 2 pieces. When you start the motor the inside of the harmonic balancer will spin but the outer part will not causing the motor to overheat.

[@stevebraun8217]

What is the brand and part number for the lower radiator hose with the spring? -Thanx

[@jeremykopp9859]

Steve Braun... thank you for watching and the comment. The one I have is a GoodYear and the part # is 38024. Let me know if I can help with anything else.

[@stevebraun8217]

@@jeremykopp9859 I'm having no luck with that part number. Can you offer further help?

[@jeremykopp9859]

Hey Steve. I’m sorry your having trouble with the pet numbers. Here’s what I would do. Take the hose you have or buy a new hose and buy the spring separate. It is very easy to slide the spring into the hose. I hope this helps.

[@stevebraun8217]

@@jeremykopp9859 Sounds good to me. -Thank You

[@pcbuys7281]

auxiliary fan?????

[@jeremykopp9859]

Thanks for watching. I didn’t include the auxiliary fan as a deadly sin. The reason being is, it doesn’t necessarily CAUSE overheating. It definitely helps prevent overheating and is a great addition. Great comment and thank you.

[@Cantinatollo1]

Number 4 about the lower radiator hoses needing to have a spring is simply a myth. Some vehicles come with stock lower radiation hoses that have a spring in them because the manufacturer tests the hoses with equipment that creates amounts of vacuum that your car will never experience. The springs are left inside the hoses. It costs them time, effort and, of course money, to remove the springs. A good quality hose installed on a properly tuned cooling system will not collapse.

[@jeremykopp9859]

I think you make some good points but I do disagree in some ways. That lower hose is susceptible to collapse with pressure and heat. The hose with spring eliminates the event of that hose collapsing. However, plenty of Jeeps run fine without the lower hose with a spring but it is a weak point non the less.

[@The177do]

@@jeremykopp9859 I looked on NAPA for the lower hose you mentioned with a spring and could not find one. Could you tell me the part number?

[@jackbooblah]

@Black Ace Gear are you a student of the Word ?

[@jeremykopp9859]

Always a student. Keep on learning!

[@gregwendt7172]

It’s an impeller, NOT a propeller

[@jeremykopp9859]

You are absolutely right! Thank you for the correction. Im a Utard... give me a break. Haha... thanks for watching.

[@stumoo4744]

You need to come up with another sin. You didn’t cover the component that fixed my overheating. Over a one year period I systematically checked/replaced every component in your video…. and my 4L still was overheating. It turned out to be my worn out harmonic balancer.

[@jeremykopp9859]

Great point and great find. Happy you were able to figure it out and maintain a cool running XJ.

[@Justdigit2]

I really don't understand why a broken harmonic balancer could cause heating issues. Can you explain?

[@stumoo4744]

On my particular Jeep, a 2000 XJ/4.0L, I had flushed the system twice, replaced the water pump, thermostat, radiator, electric fan, belt driven fan, … and probably some things I have forgotten about… then somebody suggested the harmonic balancer. Mine had split between the rubber and metal and would slip, and thus not drive the AC, water pump, and alternator properly. It would happen that when I had the hood up… visually everything appeared to be running normally. In hindsight… everything made sense. I would have a dead battery even though the generator tested fine and the battery was only two years old, my air conditioner started working better, and of course, my Jeep quit its constant overheating. However… on a 100+ degree day, in stop and go traffic, with the air conditioner on… it will still run on the hot side… but as I am fortunate enough to not be a prisoner of some metropolitan city… that is rare.

[@Justdigit2]

@@stumoo4744 Ahhhh okay... Now I understand why... Just as I thought. You see the pump running..??? But when hitting the gas and asking more strength it slips... I will look for that too then... Just set two marks on it and see if it runs away.. Thanks.... Hope I will find my cause.

[@officialWWM]

How long does a water pump last?

[@jeremykopp9859]

Thank you for watching. That is a very good question and really has a lot of factors. Depends on what water pump your using? A cheap brand pending on your amount of driving, climate etc. wont last as long as a high end performance water pump. If you are in a hot climate, the pump and system will run hotter and wear on the equipment resulting in shorter life. I believe a good average for a water pump in a fairly hot climate with 10-15K a year miles, would be 5-10 years in these older model Jeeps. Hope this helps BUT.. please dont hold me to my word on this obvious guesstimation.

[@officialWWM]

@@jeremykopp9859 thanks for your reply. Given the low cost of a water pump, I think I’ll just buy a couple of spares to keep on hand. My guess is, they won’t always be cheap, or even available as these cars are getting old now :/ Maybe changing the pump every couple of years might be a good maintenance procedure. I live in Australia and it gets incredibly hot here at times.

[@williamnagel2654]

This is 38 minutes I will never get back.

[@jeremykopp9859]

Sorry you didnt like the video.

[@georgedwinell54]

Hey ACE dare to explain how the zj clutch mounts on an XJ what with one being a flat flange and the other being female thred on !

[@v12alpine]

don't know what he was thinking, 2737 is the part number with the correct fitting.

[@user-to6jg3ts9f]

The 4.0 is designed around a 195 Thermostat. Not a 180. Using the 180 is the wrong part, and is stupid.

[@MiikeyLawless]

So in short: maintenance lol

[@davidgenie-ci5zl]

H2OH?????? H3O?????

[@lmeader7]

Very strange and weird way to try to talk about overheating xj,s but to each thier own

[@robertlanyon3528]

Well I have to think that the 8 deadliest sin is listening to you it's not called a t-stat it's called the thermostat and if you start putting 180° wine and a Grand Cherokee your engine light will come on cuz it has to have a 195 because it doesn't get up to temperature fast enough it's 180 degrees you need to learn to read something a lot of fast food or something back off and pick up a book

[@pixbyeli]

and you need to learn how to use punctuation, usually they do in books so maybe you should take some of your own advice.

[@v12alpine]

I run a 180 on my 96 no check engine light.

[@BuiltRiteTrans]

Informative Video, Um maybe. Good information, Meh.... To much talking like an amateur. Waste of time.

[@jaylarson152]

Propeller hehe.