1988 cherokee 325,000 miles,runs good. This is what I have done so far. Flushed system,changed theromostat,water pump,sensors,fan cluch,water bottle and cap and burped system and put a switch in for the electric fan. It still overheats. Could it be the type of oil. I started using VR1 50 weight racing oil.

 

ok im not sure but WHY in the heck are you using 50 wt race oil on an XJ??

Its NOT a race engine. dont get me wrong VR1 is really good oil, but 50 wt is what you would use in a top alcohol motor, or pro stock motor. race oil does NOT have the detergents needed to run this thing on a normal basis. come on now

 

First of all I have no idea what an XJ is. Second I was using high milage 20/50 with Lucas oil treatment for years. A friend suggested I use VR1 50 weight because the engine had internal noise. Well after using it the engine is pretty quite. My question is ... Could that be the reason it runs hot?

 

i can't answer you engine problem but an XJ is the lettering for a Jeep Cherokee like a jk/wj are Grand Cherokees

 

just flushing your radiator wont get everything out, it could still be plugged.

usually you have to burp the cooling system more than once, the renix engine is notorious (sp) for trapping air in the engine and running hot. i put a thermostat housing on mine from a 93 and put a drain **** where the sensor would go, drill a hole in the top of the thermostat. its a whole lot easier to burp air out of the cooling system.

 

JK is 07 up Wrangler, the Grand Cherokees are ZJ, WJ, and WK.

It is simply a manufacturers model deignation code.

 

I've burped it may times. It does make sense to take parts for other jeeps to make it work. There has to be something else.

 

how hot is it getting

 

Almost to the red mark. Even with heat on and electric fan running.

 

The only thing at this point to do is change oil back to 20/50 high milage. I live in Fla. so I'm not worryed about it being to thick. Thats the only thing that has changed in the past few months.

 

You probably have a cracked head. If you replaced everything.

 

I'm not losing any coolant and the oil is clean and nothing coming out of exhaust. compression is good also

 

If your in Florida, I would do a three-row conversion for your 88
I've a renix system aswell, and they run HOT!
I plan to do this soon:

Click 1
Click 2

 

Its always run at 210. The problem is that it starts to get hot at highway speeds about 75 mph. after about 10 15 miles