hawkins01

I currently drive an '85 jeep cherokee with the 2.5L. I just bought an '89 cherokee with the 4.0L fuel injected and automatic tranny. My plans are to put the 4.0 in my 85 along with the tranny. The problem is is that I got it from my cousin and since he go it it has had a serious overheating issue.

Here is a list of the parts he put in it trying the cure the problem:

• Water pump
• Thermostat w/housing
• Radiator
• Coolant reservoir
• coolant lines

It didn't help. It builds up so much pressure that it blows the cap off of the coolant reservoir and starts boiling coolant over everywhere. Personally I think it's either a bad head gasket or a cracked/warped head but i'm not positive.

Any help, suggestions or remedies would be greatly appreciated. Thanks.

LCFRJEEP

Ok, how hot does it normally get on the temp gauge before she blows?

Do you know if he tried to flush the system or if he ever had it power flushed?

Has he ever run it with out coolant or done anything to possibly warrent a cracked head?

How long has the new rig been boiling over?

c-loss

To start off swapping a 4 cyl to 6 cyl is a PITA. second is are you sure there are no are pockets that the closed system cant burp out? I know it sounds like a dumb suggestion but the closed systems are hard to burp.

hawkins01

I know it's a PITA to change it out seein how i have to swap the wiring harness, tank and the front end in order to be able to accomidate the 4.0's readiator. but it'll be a good project and keep me outa trouble!

But if any body has any tricks or suggestions that would make the process a little easier i'd love to hear bout 'em.

i think it was getting up around the red when it would pop the cap and i'm not sure about the air pocket idea. i currently have the head torn off to check for cracks and warpage today and replace the head gasket. i'm also flushing the head today cuz the ports are FILTHY!!

Thanx bunch.

fivendime

Bad Head Gasket, Had the same problem. I replaced everything you did and it ended up being a head gasket. Pending the coolant has no air pockets.

Plus a system flush is worthless. I have talked to numerous shops about this and you will never get everything out, or even close to it. OF course the many "5" people I talked to about it "2 radiator shop guys at 2 different shops" could be wrong but I doubt it. Thats why I talked to so many people cause I though it was a good idea.

jrhockey03

X2 I had the same problem on my last MX bike, it would always boil over, and it was only a 125. I know its not the same thing but an engine is an engine. Turned out to be the head gasket. If you let it run a bit and the rad fluid is foamy thats another indication too.