Occasional Overheating

My 2001 Jeep Cherokee Classic overheats only after being driven longer than 30 minutes at a clip. I changed the thermostat which didn’t solve the problem. I then took it to my mechanic who flushed the coolant and drove the car for 30 mins. repeating this 3-4 times. He said that it isn’t the water pump or the head gasket. I brought the car home and drove it for about a week without problem. My wife took the car out for a full day of running errands and it overheated.

Any advice would be great,

Jstax75

Have you tried replacing the radiator pressure cap? If the cap is not holding pressure the coolant will boil at a lower temp.

Ed B.

Does Your Wife’s Driving Include More Idling Than Your’s?

Did The vehicle overheat while idling or traveling down the road? I’m just wondering if the problem is with a malfunctioning cooling fan, either an electric fan controlled by sensors, or a mechanically clutched fan. I don’t know what that vehicle has. By giving information such as which particular engine you have, somebody might come up with some more ideas.

The mechanic did replace the cap. At the time I didn’t know why. Thanks for the info.

The majority of the times that it did overheat, the vehicle was on the highway. I have noticed that there is a sound coming from underneath the hood equivalent to that of a tea kettle which occasionally occurs after driving for more than 20 mins. Though I can’t find a correlation between this whistling noise and the overheating. The Jeep has a 4.0L in-line 6cyl. Thanks for the help.

First of all, define “overheat.” Does the radiator boil over or are you just looking at the dashboard gauge? Does it overheat while driving down the road or while idling in traffic?

Are the cooling fan(s) working correctly?

What is the weather like, right now, where you live? Is AC being used in the vehicle? Has the coolant been serviced regularly?

The radiator is boiling over at the fill tank while driving down the road. I checked the cooling fans while idling in the driveway and both are working correctly.

The weather here has been between 30-50 degrees so the AC is not in use. Since the overheating has started, my heat in the cabin has not been working. Unfortunately, I have not serviced the coolant regularly. Though when I took he car to the mechanic he flushed the system 3-4 times driving it between flushes.

Get the engine to operating temperature and, with the engine running, have someone rev the engine to 3 thousand RPMs or so. Carefully watch the lower radiator hose to see if it collapses. If it does you’ll need to replace it.

Additionally, with the engine still running, CAREFULLY run your hands all over every part of the radiator. Feel for any spot that’s hotter or colder than everywhere else. If you find any you’ve got a plugged radiator. Be aware that the electric fans can start at any time, and you have to be VERY CAREFUL not to get any loose clothes or any body parts caught in the drive belts.