dj31499

I replaced the thermostat on my Cherokee yesterday, and since its been replaced the engine sits at about 204 to 209 when I'm driving.

After replacing it, I went for a test drive. The engine was sitting at about 90-100 when I first started it, and after about 3 minutes of driving, it got up to about 205 until I pulled over and filled it with more coolant. (Before starting it and taking it out for a drive, I had let the engine run while I filled it with more coolant so that I could make sure the system was full, and to let any air out of it.)

My old thermostat would run at around 180-190 when I was driving, and get up to 200-210 when I was sitting in traffic. I've overridden the electric fan with because it was only kicking on periodically, for about a minute when it would get above 215, and bring it down to 210.

Now, with the electric fan running whenever I turn it on, the engine doesn't fall below 199 (rarely falls into the 100's) and sticks around 205 like I said. I'm not sure if my temperature sensor is messed up (coolant could have gotten into the connectors when changing it), because with a new thermostat and the extra fan working, it doesn't make sense that the engine would be running hotter.

PS: The thermostat I had before was the same type as the new one. It bleeds coolant into the system constantly, and doesn't just open and close as someone I've spoken to suggested

Martlor13

You do know that an xj is supposed to run at 205-210 right? You're exactly where you need to be.

dj31499

So I was running too cool before?

andrewmp6

The thermostat don't open tell 195 degress,A xj is a old engine which is cast iron those engines run hotter then a modern one which are mostly all aluminum and run cooler.You and a lot others have thought 210 degrees is too hot or on the edge of over heating,When really the jeep is in its happy temp range and perfectly fine.

nujeepguy

aluminum engines come with 195 t stats. they all run better hot
hummer 3 is alum, 195

dj31499

I never knew that was the optimal range for running, I've always been told otherwise. I replaced the temp sensor today, and it corrected it a bit, brought it down from 200 back to 190 constant for the most part. Thanks for the info

CurrySoSpicy

The electric fan was working properly too. It acts like a high limit, if the mech fan is not enough, it comes online. That's the point of it, no need to be running it all the time. If your seeing temp creep at low speed or stopped, that is an indication your mechanical fan clutch is worn out.

dj31499

Replaced the clutch a few days ago, didn't do anything for it. I do need a shroud though. Fan isn't running all the time, just when it goes over 210

dj31499

E fan also wasn't kicking in when the ac was running, don't know if that's because of the compressor possibly being bad

andrewmp6

A fan with out a shroud on it is about half working really.

CurrySoSpicy

What year is the XJ?

extrashaky

I bet we're both thinking 2000 or 2001.

Please always include your model, year and engine at a minimum, because they're not all the same.

Edited to add:

I found another of your posts where you said it's a 2000. Starting in 2000, the electric fan does NOT come on automatically when you turn on the A/C. It only comes on under two conditions:

1. The high side of the A/C reaches 300 to 320 psi. It stays on until the high side pressure drops to 235 psi.

2. The coolant temperature reaches 223° F. Then it stays on until the coolant temp drops to 217° F.

This is different from '99 and down. The electric fan in the earlier years came on at a lower temperature and always came on with the A/C. The '00 and '01 confuses people who don't know there was a change, and a lot of people have unnecessarily replaced electric fans that were working exactly the way they were supposed to.

CurrySoSpicy

Absolutely!

nujeepguy

i ran wo from oct to may with stable temp at ?210.added shroud with hot wx here and its about the same. also e fan was dead. new e fan keeps it cool. all seems ok, till 90+?? well see.

extrashaky

You can get a brand new one from Rock Auto for $11.