XJ running very warm. Please help!!

[Blaine B.]

It is.

 

[br1anstorm]

I once put a normal universal fan on my mustang and had huge overheating problems. It turned out that the mustang had a reverse rotation water pump and the fan was pushing the air back into the radiator. Check that the belt is routed properly to turn the water pump correctly.

This prompts another - related - thought that might be worth checking. If you have a reverse rotation set-up, then you need not only to check the routing of the belt and the direction the fan turns. You also need to be sure, if you replace the water pump, that you have the correct replacement pump. All the water-pump housings are the same shape and fitting (so if you get a stock aftermarket pump it may fit OK, but might still be wrong for your vehicle). If you have a reverse-rotation system, you have to check that the impeller blades of the new pump have an "R" stamped on them. If the impeller blades are angled wrongly then of course the pump won't circulate the water very efficiently, so you'll get overheating.

Hope this helps....

br1anstorm

 

[Blaine B.]

When I put the pump in last year, everything was identical to the old pump. But last year I didn't have any temp issues either.

Any comments on the temp of my trans relating to a warm/hot center console below the ebrake lever?

 

[TMXONR]

Any comments on the temp of my trans relating to a warm/hot center console below the ebrake lever?

I am running just Herculiner on my floors and no carpet. I can feel it getting warm after driving for a while.

Did you change out the Sensor for the temp gauge. I am thinking that is my problem, It reads at the 235 degree line. I am just wondering if it helped correct the gauge. I also found out that my winch cover was causing the engine to run hotter, because it didn't let the air flow around the winch.

 

[Shorty]

When I put the pump in last year, everything was identical to the old pump. But last year I didn't have any temp issues either.

Any comments on the temp of my trans relating to a warm/hot center console below the ebrake lever?

I wouldn't say mine ever get more than "a little warm" even during long periods of slow speed. Assuming your carpet and insulation are in good shape, I'd look into methods of cooling trans fluid and maybe even inspect the torque converter as it is the largest heat generater in the trans. I used to "balloon" them in the race car every season-or-so and it was usually accompanied by a sudden and rapid increase in coolant temp after a couple higher than warm-up RPM laps.

--Shorty

 

[lbsnowryder]

Blaine, just an update. I backed my XJ up on ramps so that i was at a steep down hill slant and loosened the gauge sensor. That had a good size release in air and all my heating troubles are gone. There are some rough spots in the head that trap air. It took a while but i got them out. 4.0=PITA for getting rid of air pockets.

 

[Blaine B.]

I see. But why would I have this air trapped just now? It wasn't like I replaced anything cooling system wise when I first noticed the temp being a little funky.

 

[lbsnowryder]

Good question, if temps just start acting funny with warm weather and at speed. I think everyone agrees that it's the radiator. If it heats while idleing in traffic then it's i sign of waterpump or fan clutch.

So if you have replaced all these components like i did and you still have issues then it all points to air trapped in the system.

I was just sharing what i went through to get the XJ running proper.

 

[Blaine B.]

I appreciate all suggestions!

I STILL need to get my hands on that contact thermometer so I can carry it with me at all times. As momentarily tested in the past, I believe the gauge is giving me a reading which is too high compared to actual engine temperature! As stated, the gauge was reading above 210 but the thermostat housing was reading about 179-180 degrees farenheit. Go figure, the sender for the gauge is new from the dealership.

 

[TMXONR]

I appreciate all suggestions!

I STILL need to get my hands on that contact thermometer so I can carry it with me at all times. As momentarily tested in the past, I believe the gauge is giving me a reading which is too high compared to actual engine temperature! As stated, the gauge was reading above 210 but the thermostat housing was reading about 179-180 degrees farenheit. Go figure, the sender for the gauge is new from the dealership.

So the Dealer sensor, and the aftermarket sensor both read the same to the gauge.

 

[Blaine B.]

Wait a second, I never had an aftermarket temp gauge sender. Only the origional and then now an OEM replacement from the dealership.

 

[TMXONR]

Wait a second, I never had an aftermarket temp gauge sender. Only the origional and then now an OEM replacement from the dealership.

O, well has anyone who used an aftermarket temp sensor noticed a change in the reading over the dealer sensor. Right now I am using a Wells sensor from AutoZone.

 

[Blaine B.]

I have read before that some funky temp results were the cause of a non-oem gauge sender....due to some calibration needed between the two.

So I can't tell ya for sure. There's so many different aftermarket brands, who knows.

 

[Ecomike]

I have run across something very interesting in the radiator caps section this week. Stant's 16 lb pressure caps with the pressure release levers, have two part numbers that fit the 91 and newer Jeep radiators, and older converted to open systems.

I was puzzled at first, and then I thought one of them looked defective, after some checking, I have found that the #11330 cap is designed for the standard open system and has a spring to close the overflow return valve when the coolant system is under pressure (this is the standard radiator cap most of us are familiar with).

But the #11331 cap does not have a spring to close the coolant return line valve when the radiator gets hot and pressure ups, and at first I thought they were just defective, then I noticed they were all that way, which got me to wondering why they would make such a strange cap.

It finally dawned on me that it might be a cap for a radiator that is being used in a closed system that has an internal pressure bottle like the Renix cooling systems have. So if someone used a radiator with a radiator cap on it, on a closed Renix coolant system, or installed an inline upper hose radiator cap throat assy. adapter with a cap, they could use the #11331 cap to bleed air out to the pressurized bottle automatically. I am thinking this cap must have been designed for other vehicles with a closed coolant system, but used the overflow tube and line as pressurized air vent to the closed system bottle. If not, then perhaps this is an old style pre 70's radiator cap?

Any thoughts out there on this strange cap version ????

Also, if you have an open system with overheating problems check and make sure you did not get the wrong cap. The 11331 would be wrong for the open systems, it needs the 11330 cap (for the pressure relief lever style cap anyway).

 

[TMXONR]

Ok, I have noticed intermintent high temps. Here are the last few occurances of it.

First: On the way home from Superlift. Gauge read from 210 to the needle width hotter, through some hilly windy roads, speeds were around 50-55 MPH. Then I got on the high way and the temp increased to within 1 needle width of the white line before the red area. I got off the high way and was home about 8 minutes later, the needle was halfway between the two lines.

Second: Drove the XJ to my night class. gauge held within 1 needle width of 210. When I stoped in traffic, the temp would slowly rise about a needle width. Got back up to speed, around 45 MPH and the temp went back to where it was. I get going a little faster when the speed limit went back up and the temp started going up. Outside temperature was around 90 deg.

Third: Drove the XJ to work: Same thing around 210 driving at 45 MPH, get behind someone going about 30 and the temp rises and goes back down. Get on the high way an temp rises to close to the line before the red area, get off high way and temp goes down. Stop at light and temp rises. Get to work and temp is inbetween the two lines. Outside temp was about 90 deg.
Then on the way home, Outside temp was about 80 or so. I drive the same route, only backwards and the temp stays within 1 needle width of 210 the whole time, no matter what I am doing.

Anyone know what my problem could be?

 

[Blaine B.]

Sounds KIND of similar to me. I'm thinking it's just a crazy gauge. My sender is new, however. Verify your thermostat housing temperature with an external thermometer like I did. I have a feeling you'll notice a much lower actual temperature. As mentioned before the metal thermostat housing should be withing +/- 2 degrees of the actual coolant temperature.

 

[Ecomike]

You could have a very small leak coming and going at a hose/hose clamp or the radiator. Slowing down reduces air flow while high speed heat build up is still coming out of the engine. Your clutch may be getting a little weak as it should tighten up when you slow down and the radiator gets hotter so that it can draw more air. Also the electric fan should be turning on at about 215 to 220 F. Sounds like it might not be working all the time?

Need to check the electric fan cut on and off temperature, and I am assuming you were running the AC, in which case it (the AC) might be having a problem that is adding aditional heat.

 

[Blaine B.]

I'd check the electric fan and viscous fan clutch too...but I strongly urge you to also check the thermostat housing temperature with some sort of external thermometer, be it a contact, infared, or laser thermometer!

 

[TMXONR]

It does the same thing with the AC on or off. If I have the AC on and the temp rises, I turn it off and it doesn't make much of a difference.

For the Electric Fan, I am going to say that it is always on, because as soon as I turn the key it comes on.

Can someone take a pic of where exactly I should take the temp. Also I have the Closed system.

Also could this be a sign of a crazy gauge? If I go down a steep hill when at Superlift, sometimes (most of the time, unless its a short hill) the gauge will go into the red, but once I get down the hill and on less vertical land the gauge goes back to where it was.

 

[Ecomike]

Sounds like you have a common problem, of an air bubble trapped in the block near the temperature sender. The air bubble moves back and forth when the grade of the road changes.

Your electric fan should be running all the time. How long have you had this jeep? Do you know any of its history?

What year is this beast?

The question now is, is it running hot all the time, or never? Get a $10 (on sale) infrared temperature tester at Harbor Freight. Test it anywhere on the METAL surface of the top of the metal thermostat housing where the top radiator hose attaches to engine block, that is the thermostat housing.

It does the same thing with the AC on or off. If I have the AC on and the temp rises, I turn it off and it doesn't make much of a difference.

For the Electric Fan, I am going to say that it is always on, because as soon as I turn the key it comes on.

Can someone take a pic of where exactly I should take the temp. Also I have the Closed system.

Also could this be a sign of a crazy gauge? If I go down a steep hill when at Superlift, sometimes (most of the time, unless its a short hill) the gauge will go into the red, but once I get down the hill and on less vertical land the gauge goes back to where it was.