One problem related to coolant leaking has been reported for the 2002 Jeep Grand Cherokee. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2002 Jeep Grand Cherokee based on all problems reported for the 2002 Grand Cherokee.
Vehicle low coolant light came on, checked fluid level it was low. Oil pressure dropped drastically. Normally indicates ~40 psi while at operating temperature, it now indicates 10 psi at idle, in drive. At start up, when engine is hot, the oil pressure gauge will not move until the throttle is depressed. My local repair shop owner called a local Jeep shop who informed him that the head was probably cracked, and that leaked coolant internally, causing the cam and or main bearings to wipe out, indicated by the oil pressure readings being low. According to the Jeep service shop, this is a known defect with the 6 cylinder engine. I then took the vehicle to a Chrysler 5 star service center. After explaining everything to the service manager, he said they would check it out but that he had heard of no such problem regarding this motor. The next day, he called to inform me that the motor did have a cracked head and that they would be replacing it under warranty. When I asked him about possible damage to the lower half of the motor he stated that there was no way of knowing that coolant leakage had caused the problem, that Chrysler would not warranty replacement of the engine, and that 3-5lbs of oil pressure is acceptable at idle, 10psi being normal for this motor. I contacted Chrysler corporate via email - response- they were sorry I was dissatisfied and that "intermittent problems are difficult to diagnose. . . " - follow up phone call yielded the exact same response. I am concerned that once the head assembly is replaced, both the dealer and Chrysler will try to ignore the low oil pressure problem until the vehicle is beyond warranty coverage, absolving them of any responsibility to repair it further. This is also a major safety issue with this vehicle. Should the engine fail, a serious multi vehicle accident may result from motorists passing thru the resulting oil slick, especially in a congested highway situation. It is my opinion that chrylser knows of this defect.