Hey everyone,

I've got overheating issues in my 1988 XJ 4.0L 4wd. I've replaced the thermostat, water pump, and fan clutch and still have both the overheating and now after about 10 minutes of running the thermometer is past 260 degrees. also, after shutting it off, there's steam coming from up under the thermostat.

I'd really like some help from the forum.

Thanks!

 

Some questions for you:

1. Have you flushed the system?
2. Does your heater put out good heat?
3. What color was the coolant when you drained it to replace the pump, etc.?
4. Have you checked for a leak in the area where the steam is coming up?
5. Have you pressure tested the system?

 

I haven't flushed it, and the heater works intermittently mostly when it's over 30 degrees outside. The coolant was green, but I've used a mix of colors. I can't see any liquid seeping out, but I'll definitely remove the front end and try and find it. I haven't pressure tested it as I don't have the tools. Does all this need to be done?

 

I bet your thermostat housing is cracked.

 

Well it might be now, but that won't cause the rapid overheat issue after startup.

A blown head gasket, or cracked head, will.

 

Air in system ?

 

Your system is clogged.


Stop that. Use the correct fluid. The orange and the green don't play well together. Use green only.


Get busy!


See your local Autozone or Advance Auto. They "rent" tools for free.



Only if you want to drive a Jeep and not pay through the nose for mechanics to work on it.

Also, please learn the difference between the "Reply" button and the "Quote" button. Don't be one of those who automatically uses "Quote" even when there is no reason to.