Engine Cooling problem
2000 Jeep Cherokee 6 cyl Four Wheel Drive Automatic 150000 miles
I have replaced radiator, hoses, thermastat, waterpump, electric fan. Engine is still running hot maxing out at 260 degrees after a short 15 minute run. What else can I check? Would any of these engine codes be the problem, p0705, p0138, p0135, p0132p0443 and p1491?Do not believe it is a head gasket problem, no evidence to support it.
P0705 is transmission range sensor issue, p0138 is faulty oxygen sensor, p0135 is faulty oxygen sensor heater, p0132 is also oxygen sensor faulty, p0443 is EVAP purge solenoid faulty.
The only code relative to overheating is the p1491 which indicates a faulty radiator fan relay or faulty wiring to that relay. You said the fan is working though correct?
June, 30, 2010 AT 9:43 AM
Yes the fan is working, but I bypassed the relay and have the fan hooked directly to the battery. I bought a new fan because the old one stopped working. When I hooked the new one up it didn't run. The fan is good, replaced blown fuse. Problem is in the relay. The jeep was still overheating with the fan running. Problem I have now is, The jeep hasn't been overheating past few days. Talked to several shop people, noone has a clue. By the way, thanks for the code analysis. Couldn't understand the read out answers.
June, 30, 2010 AT 9:47 AM
Is there any signs of actual overheating aside from the gauge reading? It may be a faulty reading that the gauge is showing caused by faulty engine coolant temp. Sensor.
June, 30, 2010 AT 10:01 AM
Yes, the resevoir fills up and if the jeep gets max overheating it did shut off. This only happened a few times, but like I said, the past few days it barely reached 220.
June, 30, 2010 AT 10:03 AM
Was air ever purged from the system? There could have been air built up in the system which would prevent the coolant from cooling the enging properly. Running it for a while, the air may have eventually escaped and now is why it is no longer overheating.
June, 30, 2010 AT 10:13 AM
As a matter of fact someone else said the same thing. No the engine was never purged. But that doesn't explain why the engine is heating up so fast now. I have taken out the new thermastat to see if it would help and the jeep is still heating to about just under 210 in less than 15 minutes but not going any further now.
June, 30, 2010 AT 10:37 AM
10 or 15 mins is all it should take to warm up to operating temperature though
June, 30, 2010 AT 7:47 PM
I really appreciate your help. You have been more helpful than most mechanics I have spoken to in person.