jram89

I recently bought a 97 Jeep Cherokee 4.0L and it has started overheating on me. Ive changed the water pump, thermostat, cooler temp sensor, clutch fan, and have even done a combustion leak test that came up negative but still continues to overheat. Any suggestions what I can check next would be greatly appreciated.

extrashaky

I don't see a radiator in that list. If the rad is clogged up, it will cause overheating.

Also, what are you calling "overheating" (what temp is it hitting), and have you verified the temperature with an IR thermometer pointed at the thermostat cover?

Cherojakee

Get a new cap and make sure the overflow hose isn't clogged. Check you lower radiator hose to make sure it's not collapsing, which will restrict coolant flow. Check the radiator by running with cap off.

jram89

Well at the beginning the temp gauge would rise above 210 then all of a sudden it would jump up to almost 260. Now it will just go a little above 210 but when I turn it off after driving it for about 10 min I hear steam coming out of the top hose on the radiator. I replaced the hose and made sure it was on correct and it still keeps on releasing steam from there and some coolant comes out as well. I will check the overflow hose when I get home, what do you mean by collapsing regarding the lower hose?

jram89

Also I let it run for about ten min without the radiator cap on about two days ago and the gauge never went anywhere close to 260 but after I turned it off it push out a good amount of coolant out of where the cap goes, what would cause that?

BlueRidgeMark

All of a sudden? Take this seriously: test for exhaust gasses in the coolant. That sudden spike is a classic head gasket symptom.


If that's good, flush or replace the radiator.

Cherojakee

1. Buy a new radiator cap. Factory spec 16 psi. They are designed to release pressure. If yours is old or rusty it may be stuck.

Yes it is normal for the coolant to pour out when you shut it off. Thats the back pressure from the system. You may want to put cap back on when before you shut it off. If the coolant was smooth as you watched it thru the fill neck, it's probably not your radiator. Its Probably the cap or the overflow hose. The pressure wants to release but there is no where to go. That's why your upper hose is super pressurized.

BlueRidgeMark

A stuck radiator cap will not cause overheating.

Cherojakee

I think he said it's not overheating after he changed the parts, but his upper hose is super pressurized. That way I said change cap.