99 xj overheating
05-06-2017, 04:42 PM
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99 xj overheating
I've had my 99 Cherokee for about 3 months now and occasionally the check gauges light would come on and the temp hand would go from about halfway to 260 in a few seconds, now it is doing it after about 5 minutes of driving and it will drop almost instantly after a few minutes then shoot back up again. I have replaced the thermostat and that did not seem to help. When it overheats the hoses leading into the thermostat are hotter than the radiator cap and the head, I'm not sure if that is common or not. Also during this past cold weather my heater would not work for very long at all, but this was before I started having problems with the temp. Any recommendations would help, thank you.
05-06-2017, 05:39 PM
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05-06-2017, 05:54 PM
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Sounds like you could have a few things going on here.
1. clogged heater core. Remove the two hoses going into the firewall on the passenger side of the jeep and blow on one end or use a compressor. It should have little to no resistance. If it does you can get a kit at any autoparts store and flush it with a garden hose. This shouldn't effect the jeep as far as overheating goes though.
2. For the overheating it could be a few things. Make sure you bled the air out real well. XJs are tough to fill. The best was is drive the front on ramps or jack up the front to allow air out and start the jeep while you fill it allowing the thermostat to open (just make sure its cold when you remove the cap). Then as you fill it keep squeezing the upper radiator hose to try to pump the air out of it.
3. If its overheating that quick it could also be a bad water pump, and I would suggest changing it.
4. Lastly this is the worst case scenario but you could have a cracked head or bad head gasket. One of my XJs i previously owned did the same thing and I never found oil in the antifreze or antifreze in the oil and it was a bad head.
5. Just double check the thermostat you can put it in a pan of water and bring it to a boil to see if its opening correctly.
Let me know how you make out.
1. clogged heater core. Remove the two hoses going into the firewall on the passenger side of the jeep and blow on one end or use a compressor. It should have little to no resistance. If it does you can get a kit at any autoparts store and flush it with a garden hose. This shouldn't effect the jeep as far as overheating goes though.
2. For the overheating it could be a few things. Make sure you bled the air out real well. XJs are tough to fill. The best was is drive the front on ramps or jack up the front to allow air out and start the jeep while you fill it allowing the thermostat to open (just make sure its cold when you remove the cap). Then as you fill it keep squeezing the upper radiator hose to try to pump the air out of it.
3. If its overheating that quick it could also be a bad water pump, and I would suggest changing it.
4. Lastly this is the worst case scenario but you could have a cracked head or bad head gasket. One of my XJs i previously owned did the same thing and I never found oil in the antifreze or antifreze in the oil and it was a bad head.
5. Just double check the thermostat you can put it in a pan of water and bring it to a boil to see if its opening correctly.
Let me know how you make out.
