88 Cherokee Overheating Help!!?

[kelerbel]

I recently purchased an '88 Cherokee. I was told by the previous owner that the radiator and hoses had recently been replaced. The truck ran fine, even needing a waterpump, which I replaced, and drove around for two weeks without any problems. I had realized when I was replacing the water pump that the coolant overflow box was gone completely, he had just run the hoses together. So, a few weeks later, I installed a brand new one. Ever since, it has been over heating. My temp gauge inside does not indicated this, and I didn't notice til I shut it off and heard the coolant boiling. I've tried running the air out of it through the temp sensor in the top of the block with no success. another thing I noticed is that the electric fan turns on as soon as I start the vehicle. (not sure if this means anything). I am going to try removing the box again. Does anyone have any idea what could be doing this?!

 

[cherokee_guy82]

My buddy had similar problems with his 89 after his bottle developed a crack... He replaced it and bled the system as we were told to do but it still tended to run hot. I decided to hunt down the radiator and overflow from a 94 like mine and put the newer stuff in his , then bypass the old overflow completely. It has not had any problems since and actually has never even tried to run hot... Just an idea for you as the older cooling system tends to give a lot of problems

 

[kelerbel]

Thanks. I ended up having a faulty bottle. I replaced it, under warranty, and it was ok. Until I decided to head up to the mountains. then again spewing out of the cap. I have considered putting a newer coolant system in it, but it has 207k miles...think it's time to retire it...sadly!