Nice call on deleting the heater control valve. I forgot about that. It has been so log since I deleted mine on my 89.

My ex brother in law got a 92 a few years back. He was doing some coolant work and I said "hey man, delete that heater control valve. They suck and will break at the worst times". He blew it off and said "I think it will be fine, I'm going to leave it". I said "alright man but they break but that's up to you".

Wasn't but maybe 3 months later me and him rode to pick up some food. Pulled in the parking lot right as it was getting dark. All of a sudden steam rolls out from the hood. Yeah....it was the heater control valve. It broke and coolant went every where. I just looked at him....he looked at me.

 

I also second deleting the heater control valve. Mine was working fine until I looked at it wrong and it fell apart in my hands. Anytime you can make a system simpler is a good thing.

Also, just because I only saw it mentioned once, make sure you do a proper flush. You may be surprised on what will come out of even a new radiator and heater core. Less crap clogging up your new system.

Good Luck.

 

So even though he's replaced the fan clutch within the last year, you think he should replace it again?
​​​​​​We will have some time to work on it in a couple days, I think we will do a test on the head gasket, just to be sure, and then take a look at the water pump.
thanks so much! I will let you know how it goes!

 

Knowing now that the fan clutch has been changed out, I have second thoughts.

Did the fan clutch get changed before this started happening?

Turning the heater on and it cooling off tells me one of 2 things is happening.

Either 1) you have insufficient coolant flow due to a poorly designed or malfunctioning thermostat, a blockage, or a bad water pump.
Or 2) you have insufficient air flow going through the radiator.

The fact that it doesn't overheat on the highway tells me it's air flow related. Got any pictures of the fan? Are you sure it's the correct fan blade? As in, someone didn't just grab any old fan from the parts pile and throw a random fan on that "fits" but the blades go in the wrong direction so at idle it tries to push hot air from the engine bay through the radiator?

 

I've posted this here before but...……….
Hadn't driven my XJ in quite a few days when I happened to look outside and noticed something wet under the front end. Popped the hood and found the HCV had self destructed. Delete em'.

 

Yep. Buy a 4 foot section of 5/8" heater hose, and a 4 foot section of 3/4" heater hose, and say goodbye to that thing! OR just buy the heater hoses from a later model. Same thing, but the factory hoses are shaped correctly. It just looks neater.


Since the fan clutch is relatively new, my money is on that water pump;.

 

The best way to test the fan clutch is to see if it's actually engaging and pulling air when it's supposed to. The only way to do that is to get it up to operating temperature on a warm day (~70* and over, but hotter is better) by driving it for a bit and letting it idle in drive for a few minutes. Then pop the hood and rev the engine (in neutral, of course) using the throttle directly. If your fan is working correctly, you'll get a very noticeable rush of air when you rev the engine, and you'll also hear a loud roaring sound. With a faulty fan clutch, the fan stays at a relatively low speed regardless of engine speed.

Here's a video that shows how a functioning fan clutch should behave on hot engine on a warm day.

 

Thanks so much for all the tips and info!
We were discussing the Jeep on our road trip over the last couple of days and Hubby is pretty sure the electric fan is blowing air the wrong way. When he replaced it he thought it was weird that it was blowing toward the radiator, but that's how it was when we purchased it. So he installed it the way he found it.
So he went out to take a look at the fan and darn if that heater valve didn't bust!
So we'll get that HCV bypassed and take a look at the fan. Probably look at the water pump too, just because.
Will keep you posted!
thanks again for all the info!

 

Oh, I wish you had mentioned that sooner! That is NOT correct. It's supposed to PULL outside air from the front of the radiator and blow it into the engine compartment. If it's pulling hot air from the engine compartment and pushing it over the radiator, it ain't gonna work very well!


That might just be the whole problem. Fix it and find out!

 

I can't believe I forgot to tell you this. I used to have a 94 XJ and we (me and my daddy) hot wired the electric fan up and accidently had it blowing in reverse. Took us a while to figure out what the problem was. That has been 8 years ago now, he's been dead for 7. That's probably why I forgot. So I guess I didn't cover everything. I made sure when I hot wired my 89 up that I did it the correct way. I prefer them hot wired to a switch so I can control them.

If that is hooked up backwards of course you will run hot and extremely fast at slow speeds and in traffic. Once we flipped the wires it solved the issue and it never ran hot again. Hope this is all it is and it turns out you have an easy fix.

Sorry I forgot. I'm disappointed in myself.

 

Don't be disappointed in yourself, you've been a big help. You got us thinking and talking about stuff, then when we started talking about fans I read a thread where someone else had their fan blowing the wrong way . Like I said, he thought it was odd that it would e pushing air, but that's how it came to us, so he just thought it was correct.
Hopefully it will fix the problem or at least make it better.

When draining the coolant system is it normal for just a smallish amount ( half gallon or so ) of coolant to come out when the radiator cap is removed and the stopcock flipped? Then when the lower coolant hose is removed the rest of the coolant comes out via the radiator? Hope that makes sense, Hubby was wondering why it doesn't come out more through the radiator once the system is opened.
thanks

 

Normal.

A word of advice for future adventures - don't touch the drain petcock. They have a habit of breaking, and you can wind up needing to replace the radiator. Just disconnect the lower radiator hose. Much mo' bettah.

 

he took out the heater valve, replaced it with coolant hose.
Took off the water pump, it had a little rust and a bit of resistance to it, so he replaced it.
He re-wired the fan so it's pulling air across the radiator, said it cooled the engine off noticeably.
and is now taking it for a spin.
Crossing fingers that it runs cooler!

 

he said so far it looks the same, but he is taking it up to the road that it overheats on to know for sure

 

He took it up in the woods where it would normally overheat, and it did not.
It's 30 degrees cooler than it has been, and raining, so we think it's too soon to tell for sure.