savagess2546

I've searched a bit on the net and found no definite answers about this.
I'll give you some history. Maybe 7 months after getting my Jeep I was driving down a river bed, noticed my Jeep was getting hot (from running it hard), and I stopped and shut it off until it cooled down. Now this may just be coincidence but I thought I'd throw that in. I started paying attention the temperature a bit more later on and noticed it was running a bit warmer. 210 freeway but sitting still it would idle up to 220s.

Since then I've replaced the radiator, fan clutch, thermostat several times, water pump, and heater switch (because it broke during a radiator replacement). None of this helped. Got to the point where, when idling, it would climb up to the halfway point between red line and 210. I figured about 240 or so.

Finally took it to a mechanic who determined that the auxiliary fan wasn't turning on due to computer issues. They replaced the computer. Since then it doesn't get to 240 but it still climbs to 220-230 or so when sitting still.

No leaks of coolant but the reservoir bottle is slowly going down. Was told it might be burning off coolant.

Only advice I've been given is it to put a 160 degree thermostat in but I'm not sure what it'll do since I have a 190 in now that I assume is just staying open all the time.

It's a 1995 Jeep Cherokee Sport, 4.0L, auto.

Roler

Loosing coolant without a visible leak is potentially not good news and pointing towards cracks in headgaskets and heads etc. What is your coolant color like and is there any muck sticking on your radiator cap or oi lfiller cap?

A 160 degr thermostat wont fix your problem, it will open up sooner (at 160) but if you have such a substantial overheating, then it will not fix this.

Having said that: how old is your radiator cap? This is an overlooked maintenance item, and a poor sealing cap can actually cause overheating. Any dried up coolant around the radiator cap (this appears like white dried up fluid)?

savagess2546

Sorry for the late reply. I never got notified of the response. That'd be pain if it was cracks in headgaskets and what not but I thought you'd see water/coolant in the oil if that were so?

And there's not any gunk that I've seen. The coolant reserve bottle is gross in the bottom but under the radiator cap is just bright green.

And I actually have a new cap on it. Nothing changed from old to new cap.

That time I mentioned where I ran it hard, the temp gauge was pegged over and as soon as I noticed this, I turned it off. Not sure if that was the best thing to do. So maybe that did something?

Would a pressure test determine if there's a leak somewhere?

savagess2546

*bump*

=(

djb383

Fan shroud intact/in place? Dash gauge reading verified? Don't take any more advice from whom ever suggested a 160 stat.

884x4

Fan shroud does matter! It gets me 10 degrees at least cooler idling with it on vs off

Firestorm500

You've done everything except for pulling the head and inspecting the head gasket.

savagess2546

Everything intact and I had a friend use a temp gun and it was reading the same as the guage.

I'm having it pressure tested right now so we will see.

blkonblk

my 96 4.0l has the same symptoms. new rad cap, newer radiatorand new Tstat. I dont se any coolant in my oil but i still run over 210 at stand still or heavy traffic but at or under 210 if im on the freeway....hmmm

B-17 guy

Hi, I m new on these forums. First post as a matter of fact! One thing I've learned about forums is to always use the search function! I just got my 96 Cherokee a month ago and noticed the same exact issue. I found this forum through the power of the web, and used the search function. I learned that this a very common issue as apparently the computer controlled aux cooling fan is set to kick on at 218F. If you are not sure if you aux fan works, you can disconnect the electrical plug on the thermostat with the engine running and the fan will kick on about 6 seconds later(you'll get a check engine light code from doing this). This way youll know the fan works.
You can also kick the AC on and the fan will operate.

By the way, I'll also found out that the mid 90's cherokee floor pans like to rot out. I advise climbing underneath and having a look see. And pulling up the carpet and look there too. I'll be replacing my floor pans soon.....

Firestorm500

Your Jeep is behaving normally. His isn't.

savagess2546

Pressure test showed good pressure. Guy said the pressure was going down really slow. He recommended some of that liquid copper to plug up any small leaks.

Both my radiator caps appeared to be faulty. Stock one wouldn't hold pressure at all. Stant one would lose pressure. Ordered a new cap.

As far as the fan is concerned, I'm going to wire up a switch so I can flip it on when I need it but still have it come on with the AC. The fan works but sitting still while the guage reads 220, it won't come on. However it turns out my guage is high by about 13 degrees.

savagess2546

Its only when I'm driving slow (traffic or offroading) or stopped that the temperature goes up. 35+mph is fine. Unless I'm climbing the grapevine...

But that's when the tranny is working hard as well.

Pelican

You said in post #8 that gauge was reading same as system temps checked with a gun. In #12 you seem to be saying that gauge is high by 13*?

I'm probably just reading wrong bu thought I would ask.

savagess2546

Well I did say that. In the earlier post I had thought the guage was accurate but now I'm finding out it isn't. Sorry for any confusion there.