Hey everyone I just bought an 89 jeep Cherokee and am slowly going through the jeep to get it up to par. It is running but overheating VERY quickly after start up. I have the closed cooling system still. I replaced the t stat, the water pump, the radiator and coolant reservoir and it's still overheating on me. I'm kind of at a loss of ideas right now, any help would be greatly appreciated! Thanks again.

 

While you had the radiator out you should have converted to an open system. But I would change the fan clutch because it sounds like that could be it.

 

Check for air bubbles first. If that doesn't help I second the fan clutch. might be replacing it with a ZJ fan clutch later on today when I get my radiator rodded out. You can test your fan clutch by folding a magazine hot dog style and while your XJ is at 210, stick the folded magazine between the fan blades and if the magazine stops the fan, you need a new fan clutch. (Hayden #2737)

 

With the engine cold, take the cap off the overflow bottle and start it, let it run a a minute or two and see if bubbles come up through the overflow bottle.

 

you might make it easier if you park nose up on an incline when you burb the cooling system. And my rule of thumb on fan clutches is , less than two revolutions when cold ,clutch is good. engine off , spin by hand .

 

Fan clutch been checked

 

I was suggesting checking for bubbles as a quick way to check for a head gasket leak, not for burping.

 

Yep. Time for a compression test.

 

So the fan clutch is good I just got done replacing all of the heater hoses and topping off the system now I have a leak in the brand new coolant RES. Once I put the new one in Tmro I will try the suggestion of Parking at an incline to burp the system. Thank you everyone for your help. I'm really hoping it's not a blown head gasket. If so what are your thoughts on that bars gasket fix? Bad idea or worth a try?

 

I do have bubbles coming in the coolant reservoir after it gets to 210.

 

It's nose down for burping. Mine was doing the same thing. Burped it and that helped a lot. Now I went to an open system. Way better. Never heats up now. Super easy.

 

Get it pressure tested, good chance you have a head gasket leak. (it could be boiling, but that's why you pressure test it).

 

Ok I've heard both for burping head down and up? I'm pretty sure it's head down. Next step like you all have suggested is a pressure test. How do you all feel about bars head gasket fix?

 

That "gasket fix" crap is a no no. Do not even think of using it. A head gasket is not all to difficult or expensive to do yourself. Just eliminate the thought of using bars.

 

Also, you burp a closed system with the back of your jeep higher than the front. This is so the air will travel up to the back of the head where you burp it and it can escape