Peter Aue

This is our third XJ. Never really had a problem with any of them until this summer. Driving along one day, the temp gauge suddenly jumped to around 235. Not a slow climb, but a jump. I pulled over and found that the cap was puking coolant, and the over flow tank was doing the same. In the prior year I had replace the water pump, radiator, hoses, thermostat,and fan clutch. These things were replaced from a maintenance standpoint, not because of any overheating issues. I had just finished replacing the engine in our Ford F-350 turbo diesel and did not have it in me to do anymore heavy engine work. I'm old ! I had the vehicle towed to the shop of a friend, suspecting a head gasket and or a head. They pulled the head and sent it out to be magna fluxed. The head gasket was also inspected, and found to be intact. The machine shop said that the head was not cracked or warped. They re-installed the head,and informed me that the engine still overheats. We are in the third month of having this car in the shop, and the owner is chasing ghosts. I say that the machine shop screwed up, and that the head has a crack in it, that does not expand until the engine comes up to about 225 degrees. The amount of pressure in the cooling system is in far excess of 16 lbs. I'd really like some input on this as I am out of patience with the situation.
All input is appreciated.
Peter

00t444e

Have you flushed the cooling system and checked the water pump and thermostat?

Peter Aue

water pump has less than 3000 miles since replacement. Shop removed it to make sure that the impeller is not spinning on shaft. Coolant has been flushed several times. Radiator has been replaced, along with correct thermostat.
Perplexed!!!

smooth move

me too. having cooling problems too. flushed radiator and block. will run at 210 untill on hwy for 10-15 min then on up to redline and boil over. elec fan quit kicking in, couldn't find reason, so i wired it to a toggle switch and turn it on manually. next move is to replace radiator , water pump and thermostat. i've had this 92 xj since 99. it's mostly a camp jeep now, but i like to keep it legal and able to run on the hwy for runs into town.

F1Addict

I'm assuming you ruled out a faulty radiator cap or thermostat prior to pulling the head?

I recommend following this thread. I'm working through the same problem.

investinwaffles

Is it an airflow issue, or coolant flow issue?
Airflow issue symptoms would point to it overheating at slow speeds or at idle, and a coolant flow issue (IMO) would be overheating over 45 mph. Or maybe a coolant pressure issue if the system isn't bled or rad cap isn't holding pressure.

Airflow related, check the fan clutch - the e-fan doesn't even turn on in my XJ. You are 100% sure the radiator isn't plugged up? A Spectra Premium replacement rad is around $70 online.
Also make sure the AC Condenser and Radiator fins are clean and not covered in mud or road film/oils. Definitely won't cure the issue but it's good practice.