overheating

[thewitnit]

99 Jeep Wrangler New radiator, new water pump, new thermostat and hoses. Still overheats.
What else is there?

[MagicRat]

Do you have an accurate temp gauge on this? Sometimes, other defects, like a blown head gasket mimic overheating symptoms.

[thewitnit]

Will do a compression check and see about that. But so far no water in the oil.

[fredjacksonsan]

What engine and how many miles?

Does it overheat just in traffic, or on the highway also? A bit more description of the conditions that cause the overheat please.

Do you lose coolant over time, or does the level stay where it is?

What is the condition of your radiator cap?


If you have the 4.0 and are losing coolant, you may have the "0331" head. Search the Cherokee forum and you'll find posts on it - short story is that these develop hairline cracks after 90k miles.

If you are NOT losing coolant, you may just need to 'burp' the system. Park the Jeep with the front end about 1 foot higher than the rear. Take off the radiator cap and start the engine. Let it run, watching the radiator for flow (and keeping it full) and the temp. gauge for overheat. If it's got some air trapped in the system, the level in the radiator will drop as the thermostat cycles.

Post back with your answers and we'll be able to help more.

[thewitnit]

4.0 liter. New cap. Overheats in both traffic and highway. Not losing coolant.

[fredjacksonsan]

Have you tried burping the system yet?

[saturntech]

could be the clutch fan seizing

[mastertech1964]

could be a cracked head ive also run into guys who did their own waterpump and put the 1 long bolt in the short hole and cracked the cylinder wall in number one cylinder another possibility is that you were given the wrong water pump a 4.2 pump will fit a 4.0 but the pump rotation is opposite due to the 4.2 having vbelts and the 4.0 having a serp belt