Another Overheating Thread

Hello, Ok so i will be going down the road at about 65 for 15-20 minutes and my XJ starts to overheat. After about 25 minutes of driving my XJ is about to 260*. I have changed the thermostat and did a cooling system flush. The head gasket was changed about 2 1/2 years ago. Not sure really how long they last. I just know thats when it was changed cause I have the records from the previous owner. My fans are working fine. Please help me out. Just some info. I have a 1992 XJ Limited. 4.0, AW4, NP242, Dana 35 (R), Dana 30 (F),

Start with the easy and cheap stuff. A new, tested at the counter and verified to be good, radiator cap. Lock for dirt, blockage in the condenser and radiator blocking air flow. Inspect the exhaust manifold closely for leaking exhaust blowing on the block, especially the flange donut (have an muffler shop inspect it if needed, they usually do free ones), and the manifold (loose bolts top or BOTTOM), looks high and low for signs of small, slow leaks at the hose ends, radiator...., and check the coolant level in the radiator and the overflow bottle. Also check the overflow hose, radiator to bottle, for any cracks letting air in!!! Check the actual T-Stat temp with a cheap infra red hand held gauge. The dash gauges can be wrong, sensor can go bad, bad ground, wiring...

Do all this before anything else. If that fails do a coolant flush of the block and radiator. Ask for details....

It's a long list and it may be one or a combination of things. Check the bottom hose for a spring, the easiest way is to crush it between your fingers mid way between the pump and the radiator. The springs can actually rust and rot.

Put a catch can under the drivers side and open the radiator, run it up to operating temperature some coolant will spew, though not a lot. Watch and see if bubbles continiously come to the top. It may be another head gasket.

I hear the test kits for exhaust n the coolant have gotten better, the last time I tried one it was negative and I had a head gasket leaking exhaust into the coolant.

Pulled and pressure washed my radiator fins today, they were pretty plugged and so far seems to help quiet a bit. Also removed my plugged AC condensor since my AC doesn't work anyways. Tomorrow will be the test, supposed to be a warm day

Chuckanut said:

Pulled and pressure washed my radiator fins today, they were pretty plugged and so far seems to help quiet a bit. Also removed my plugged AC condensor since my AC doesn't work anyways. Tomorrow will be the test, supposed to be a warm day

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indeed, one of the usual suspects, LOL.