gpittman

i have a 98 cherokee with the 4.0. this is the first jeep ive ever owned and im happy with it thus far. the only issue im having with it now is it is overheating. this started about a week ago. i replaced the tstat and it was good for about a week. the water pump is less than a yr old, i ran radiator flush and cleaner through the system. i have no heat and it is still overheating is there any suggestions out there for me

brianrich07

Thats a XJ for ya! I live in Texas and tried every thing under the sun. If you live in a hot climate, buy a 3 row rad. It helps alot. Is your fan clutch and efan working correctly?

77olds

You have no heat but the engine is overheating?

Sounds like a restricted heater core to me.

VTJeep

Is it cold or warm where you are? No heat in cab would indicate heater core. Flush it separately with water. Also back flush it. This can take some time, but is worth it do get any/all build up out.

What does your coolant look like? Check the rad cap and the overflow bottle at least. Maybe drain some out for good measure..

What does your intake setup look like? OEM, aftermarket? Clean air filter?

How's the oil?

How do you know it's overheating? Verified with temp gun on tstat?

ZINGGG

^^ All that VT said.

And flush the hell out of your heater core

shoggoth80

"You have no heat but the engine is overheating?

Sounds like a restricted heater core to me."
-Word. No heat, and overheating... sounds like a heater core issue.

Pressure test your cooling system. No heat screams low coolant to me. Heater cores are a pain, but you can bypass that if you live in a warm climate. Seriously hoses, t-stat, caps, and coolant are cheap.

PNWjeeper

Check easy cheap stuff first.

#1 verify temp with heat gun you want to make sure it's overheating before replacing things. The factory temp sensor can be faulty and is inaccurate.
#2 coolant level would explain no heat
#3 mechanical fan SHROUD, without this all that fan is doing is pushing hot air in circles, with it the mech fan pulls cool air through the rad.
#4 radiator cap
#5 mechanical (clutch) fan, you can test this by first pushing the fan with the engine cold it should move fairly easily with the engine at operating temp fan should be more difficult to move. This method can be inaccurate but is an easy test.
I believe that I ordered these by cost as well as probability (as far as the overheating issue goes), I may be wrong on some of this if so someone please correct or add to this.
Hope this helps good luck.

KCXJKID

Try to blow through the heater core for flow. If its clogged take a high PSI air compressor and run the air hose in the inlet hose of the heater core. Shoot constant air in there for over 2 mins even if it tries backing out. It applies a little more force than liquid flushing solutions. Works for me everytime. GOOD LUCK

Edit: If your coolant is at all rusty consider the water pump fins rusted and gone. Take it one step at a time

Salden Hund

With the Pump being replaced but a year ago, I'd removed the heater lines and splice them together. It should form a U-bend that goes from Water pump to T-stat housing. If it stops over heating, viola. This was my issue. I replaced everything and ended with a blown rad. after replacing that, the lines became spliced. Ran cool ever since. I can detail this if you like.