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View Full Version : Overheating problems with my XJ



DirtyXJ
04-29-2010, 10:30 PM
I have a 94 U.S. marshals xj it has 198k i put the last 18 k on it. I replaced my thermostat, water pump, radiator, fan, i ran my electric fan to a switch on my dashboard. That helped for a little as long as i always keep the switch on. But now after i start the jeep within about 3 min with the electric fan on or off the temp gauge red lines but it doesent seem like its really overheating sometime the gauge gets cooler after i red line it. but it doesn't get to much cooler im kinda stuck now not sure what i should try next?

limegreentj
04-29-2010, 10:39 PM
maybe your temp gauge is ****ed?

tjblair
04-29-2010, 10:41 PM
Are there exhaust bubbles in the coolent? If it is heating up that quick I would think maybe its a head gasket.

limegreentj
04-29-2010, 10:43 PM
he said he doesnt think its really heating up though, one way to tell is to point a good laser thermo on it. if it is heating up, i would suspect head gasket or maybe a plugged up cat.

tjblair
04-29-2010, 11:05 PM
Its easy to tell if it is Too hot or not, just grab the upper hose. If it does have a bad head gasket. When he " red line " it, it probably blows a bunch of air into the cooling system. When the air gets to the temp sensor it causes the guage to drop. It's just a guess but I would start with a compression test.

sethman15210
04-30-2010, 06:09 PM
maybe a clog, i had a chunk of crap break loose from the heater core and plug the lines and made it overheat fast. it jammed into the return line from the heater. was a pain in the a** to figure out. or id bank on a cracked head gasket between the cylinders, hard to tell without a compression test. and it doesent leak or mix any of the fluids. my wifes volvo did that 2 months ago. mainly made the engine heat up really fast but still drove with no other problems

xjmudder
05-02-2010, 09:25 PM
Thats funny I'm having the exact same problems, I even ran my fan to switch on the dash just like you did. I think its a problem with the temp sending unit. Im not redlining al the time like you are but its still getting hot if I have to run up hill for a long time. Thats the problem with XJ's they have some kind of electrical sending unit for eveything. If I figure it out Ill let you know.

jim91303
05-03-2010, 07:26 PM
mine did that too ..... bad head gasket. and it did not blow back into coolant. was blowin out the exhaust