1994 Jeep Cherokee Sport Overheating issue

I have recently had a problem with this vehicle with overheating issue
It is a 1994 cherokee sport 6 cylinder, 4.0L

After driving for awhile anywhere between 15-22 minutes this beast is overheating like nuts. On the gauge its reading in the neighborhood between
240-260 degrees F.

To combat the problem I have already replaced the electric fan, seeing that the last one wasn't working,the thermostat, replaced the water pump and all of the hoses.

Even after replacing these parts its still running hot around the SAME tempatures.......

What else can is there to do?

I have pretty much stopped driving at and if it is only short distances.

Some help would be much appreciated seeing that I need to get this Jeep running effieciently so I can continue my day to day business without the fear of getting stuck out on the road somewhere.

Any information I haven't provided I will, because I have probably left out some information.

Have you checked the radiator fins?? They plug up with bugs and other things. That would reduce the air flow that will take the heat away. Even plugged AC condensor fins (that sits infront of the rad) will do the same.

If the tubes in the rad are plugged with mineral deposits, that will reduce the flow through the rad and less heat is removed. You will need to take it to a rad shop to have that checked.

Sometimes the cooling system will get an air lock in it that will block the flow and it will over heat but I don't see a history that would suggest thats the case here. Its worth keeping in mind when you work on it though.

The last thing is a blown head gasket or other combustion leak into the coolant. This is the most sever problem so I would eliminate the others that I've mentioned first.

Maybe this will jog someone elses memory with some other causes as well.

Good luck

JD

Hmm Now there is some useful information I think..

I forgot to mention that yes I DID replace the head gasket.

Also I am not leaking any coolant. I checked all the hoses for splices or cuts and nope. Didn't hurt to double check though.

I didnt check the fins yet. Maybe it has stuff in it.
I guess ill take it to a rad shop to check for mineral deposit plugs?

I'm running out of ideas of what to do.

I guess ill take it to a rad shop to check for mineral deposit plugs tomorow and see what happens. :banghead: argg

You said you probably left out something.............
How long ago did you replace the head gasket??

Some head gaskets are mirror image for the head bolt holes but almost none are for the cooling passages.

If the head gasket is flipped end for end, the coolant passage at the front of the block is left open and the passage at the back of the block is blocked. Result is that the coolant circulates in the path of least resistance at the front and the back, with no circulation, will over heat - guaranteed.

This may or may not be good news depending on when the gasket was replaced and when the overheating started.

JD

Correction:

Last night after I read this comment and slept on it I realized

NO! I haven't replaced the head gasket!
I just realized the gasket I replaced was for the thermostat cause I was thinking about it and NO I have not. I confused the 2 ugh.

That could very well be the problem seeing that everything else has been replaced except the entire radiator and that.

I've yet to take it to a shop yet, but that will happen within the next 3 hours. Ill ask them about the mineral deposits you mentioned and etc while im there.

Hope Ive limited the problem down to these things cause im running out of $$$. uh oh.

Well Forgot to take it to the shop as I was incredibly busy this week and weekend.

So I did a "quick fix" and removed the thermostat entirely. With the thermo Removed The tempature dropped slightly but it is now driveable in the neighborhood of 230-240 instead of the whacked 260 zone.. It gets to 240 when I idle for a long time. But isn't this still bad?

I guess I can live with this. The only other thing would be to take out, clean and gut the radiator but I figure ill go a week first with the thermo off and see what happens.

Question: If the tempature jumps up back to hot temps of constant 240 and up. Would this clearly indicate then that there is build up in the radiator?

XduradoX

The removal of the thermostat for operation lik you intend has the somewhat the same effect as the reversed headgasket.

It will cause the rear cylinders to hotter than the front.

It doesn't look like it has helped that much either.

Best thing is to get it to the rad shop as soon as possible.

JD

JD

Is this one of those closed cooling systems which are prone to air being trapped in them. You say you replaced the stat gasket, I assume that means you replaced the stat. I've read that some of the XJ's have a closed system that tends to get air in and is a real bi**h to get back out, causing major heat problems. And how about the pump, can you turn on the heater and get hot air? Search through some of the older posts/threads, there was a ton of info out on this about a month ago...specific instructions on what to do...

Sounds exactly like a problem that my brother had. He replaced everything BUT the radiator and it was still running way hot; he finally took it to a radiator shop and they found that the radiator was not flowing 100%. They were able to flush it and restore the flow. So before you go and do the expensive (in either time or money) head gasket (and I'm not saying don't do it) have the radiator checked out.

Well guys I appreciate all the feedback and responese I got.

I finally saved up some dough to take it to a shop this past weekend and as some of you have guessed it was the radiator after all.

3/4 of the mother was clogged with mineral deposists thus negating any cooling effect. Mechanic was like HOW the )#($*)#( have you been driving this thing!!

Anyway had to replace the radiator so it was majorly clogged with some major corrusion and etc.

Im guessing 190$ was not bad for an new radiator with warranty?

Don't know much about that but I took it and wooo problem fixed.

Once again thanks for all your help guys.

I will be around for awhile :smile: