4 hour trip produced elevated cooling system temps.

I have noticed that since I replaced radiator, water pump, hose, blah blah blah that my XJ runs about 210 all the time, with one exception.

Anytime I drive 70 to 80 mph during a 95 to 100 degree day, the temp will rise to 225 degrees (first hash mark past 210) and stay there until my speed drops to 50 mph or lower, then it will drop fairly close to the 210 mark again.

If it is cooler outside, like it was yesterday evening when we came home, the temp will go mid way between 210 and 225. As an experiment I turned off the A/C and after a couple of minutes, the temp dropped to just above 210.

I've read here before about the A/C causing the cooling system to heat up, but I do not remember if there is something I can do about it. A/C under charge, over charged?

Maybe it isn't the A/C, maybe the transmission is slipping, or the CAT is blocked. The torque converter unlocks if I tap on the brake (I see the rpms go up then back down).

M XJ is doing the same thing for a couple of years. Sustainned speed of 85+ MPH raises the water temperature. Reducing the speed to 75 and below the temps will go back down to about 210 I am not sure I know what causes that. This is all on flat roads.

When I first noticed that, I had replaced the water pump, thermostat (from the stealership) hoses and a three row all metal (brass) radiator. These was after a through system flush.

Funny but at times I push the XJ up long hills at 75 MPH and the temperature stays at 210.I am thinking it may be the water pump or the radiator not allowing enough air to pass. This has not been a problem for me since I usually drive at 70 or below;..... well, it is more of a nusience than a problem. I promised myself tht one day I will try to sort this out . One day.


It is funny but when I drive long hills at

Sometimes I think that air flow is blocked by the dual Derale # 16928 electric fans. They have a large diameter motor. This have always been a concern to me. I am running them for almost 4 years now and would not go back to the OEM mechanical fan.

That may be my next experiment. Take the fans off and go down the highway at high speed and see how high the water temperature get.

The in radiator transmition cooler is used first then an external (Ford Explorer type) cooler in front the radiator befor the fluid is returned to the AW4. At high way speeds, the AW4 temperature is always below the engine temperature.

After 3 years I have found the solution to my heat creep on the highway.

Things tried...

A good flushing (multiple times coolant nice and green for years now) along with changing all hoses and belt.

CSF 3 row all metal radiator FAIL
CSF small leak repaired and flow test performed! FAIL
Heavy Duty Grand Cherokee fan clutch FAIL
High Flow thermostat housing FAIL
High Flow thermostat (195 degree) FAIL
FlowKooler High Flow Water Pump FAIL
13k BTU automatic transmission cooler added FAIL
Cut a big a$$ hole in my hood and put on a cowl induction scoop! FAIL
Performance Radiators 1 row aluminum/plastic radiator $140 shipped SUCCESS!





Now I won't say that all the things I tried were a complete failure. All the prior mods did make some different to the coolant temps, it just didn't resolve the running hot at highway speeds. I have only tested this radiator once, yesterday, on the highway but at 78 mph for 16 miles in 94 to 96 degree air temps (sun blah blah blah) the needle went just past 210 hash, but still touching the hash mark. Dropping down to 65 mph I could see the needle moving south instantly. I have 32" tires with 4.56 gears, so I run about 2800 to 3000 rpm at highway speeds.



The coolant temps drop well below 210 at speeds under 45 mph and stay there even in bumper to bumper traffic. So what I appear to have done is found the problem that was causing the heat creep THE ALL METAL RADIATOR (copper/brass) and resolved the typical running hot issues that many XJ's have at idle or low speed.

I'm still testing as is several people on my site, so I'm just sharing my findings here with you and that I believe it is the solution.

BTW, I have a 3 year old CSF 3 row all metal radiator that I'll make you a deal on! It's in great shape!



Oh and the next time someone tells you to remove your winch and lights because you're running hot on the freeway, tell them to eat caca

most often cause of the problem is clogged or damaged cat converter

Excellent, it seems my XJ heats up to 210+ and never comes back down until I shut it off, keep us posted on the log term sucess of the new rad. I have to put a new head gasket in the XJ this fall I may just add this upgrade.

ehall said:

most often cause of the problem is clogged or damaged cat converter

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I forgot to mention that I also changed the catalytic convert when I changed the muffler. I guess it was already clear that a clogged cat wasn't my issue, nor is the the spring missing from the lower radiator hose.

It is funny but I completely forgot about that thread. The big surprise was, when I noticed I actually contributed to it.

Wading through all the XJ over heating threads in the forum, the really stubborn over heating problems were solved by installing a different radiator and usually a none OEM radiator. Even those who race their XJ in one form or the other have a non OEM radiator and boast of their ability to run hard and stay cool. I am also of the opinion that having an AW4 with the cooler in the radiator do not help either.

I have been out of the US most of 2008, 2009 and all of 2010. I am back in the US for 4 months but have not driven the XJ nor have I done work on it. I DD a 18 year old Toyota pickup here in Jacksonville Fl. The XJ is in Miami. If I remain in the US, I will remake the cooling system including the installation of an after market rediator preferbly a dual 1" core all aluminium unit.

I am glad you finally have the problem beat. :yelclap:

techno1154 said:

It is funny but I completely forgot about that thread. The big surprise was, when I noticed I actually contributed to it.

Wading through all the XJ over heating threads in the forum, the really stubborn over heating problems were solved by installing a different radiator and usually a none OEM radiator. Even those who race their XJ in one form or the other have a non OEM radiator and boast of their ability to run hard and stay cool. I am also of the opinion that having an AW4 with the cooler in the radiator do not help either.

I have been out of the US most of 2008, 2009 and all of 2010. I am back in the US for 4 months but have not driven the XJ nor have I done work on it. I DD a 18 year old Toyota pickup here in Jacksonville Fl. The XJ is in Miami. If I remain in the US, I will remake the cooling system including the installation of an after market rediator preferbly a dual 1" core all aluminium unit.

I am glad you finally have the problem beat. :yelclap:

Click to expand...

If you are hiding from the authorities you should turn yourself in, if you're part of the war on terror, thank you for your service!

Yeah this has been beyond frustrating. Funny thing is the point that I was willing to try a single row aluminum/plastic radiator again was because of mounting evidence (discussions on my xj site) that the factory radiator performed better than the all metal cooper/brass aftermarket radiators.

My 1998 came with a 2 row aluminum/plastic radiator, but I only just found this out about a week ago when a xjtalk member had a buddy that works at a Chrysler dealership look it up.

The Chrysler OEM radiator was $275, this Performance Radiator was $140 shipped. I've been burned so many times before trying to fix this problem I wanted to spend the least amount possible.

Why is it always the last thing you try fixes a problem!!!! :laugh2:

I do not know why we like to try the most exotic fixes first and if they fail, then we go for the obvious.

No, I am not running from the authorities and I came to the US too old to serve. I work in cellular. Since January of 2006, I work with companies that do work in the caribbean. Being a born citizen of the caribbean and since the year 2000 a nautralize citizen of the US. I think I should enjoy the best of both worlds. atriot:

techno1154 said:

I do not know why we like to try the most exotic fixes first and if they fail, then we go for the obvious.

No, I am not running from the authorities and I came to the US too old to serve. I work in cellular. Since January of 2006, I work with companies that do work in the caribbean. Being a born citizen of the caribbean and since the year 2000 a nautralize citizen of the US. I think I should enjoy the best of both worlds. atriot:

Click to expand...

lol

Well keep in mind that one of my FIRST attempts to fix the problem was to replace the radiator with a 3 row all metal, and the BELIEF that I couldn't do better than that in the radiator department caused me to keep looking for the solution elsewhere. The CSF 3 row all metal radiator WASN'T the solution to my problem. It helped, but it was unable to handle the heat being generated at highway speeds.

Where is a good place to buy this performance radiator?

rockhead said:

Where is a good place to buy this performance radiator?

Click to expand...

Well maybe you can find a cheaper place, but I got mine from Amazon for $140 shipped.

Mudderoy said:

Things tried...

CSF small leak repaired and flow test performed! FAIL

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I also have a CSF 3-row, purchased in 2005, and it's got a very minor leak where the core meets the tank.

Where was yours leaking? How did you fix it? How much did it cost to fix the leak? I'm thinking of getting the solder and fixing mine myself.

My jeep never overheats in high temps, but I have an AX15 transmission, with no AC.

Mudderoy said:

Why is it always the last thing you try fixes a problem!!!! :laugh2:

Click to expand...

Because once you fix the problem, you stop trying? :roflmao:

Thinking about trying this one. http://www.genesisautoparts.com/product/RAD14077X2335-2A.htm


I can not find many reviews but..