Rapid overheating issues ‘01 XJ
Hello all, I just picked up an ‘01 XJ about a month ago. Drove it home (about an hour) with no issue. Next day I start working it over, fluid changes, filters, etc. ever since then I have been having some crazy issues with overheating. In about 5 minutes of running at operating temp the gauge will jump from 210 all the way to 260 in less than a second. Occasionally it will jump between 260 and 210 very quickly, super weird. I did verify the actual temp through the OBD2 to see if it was weird sensor issues and it seems to be fairly accurate.
Here is what I’ve already done
-Replaced the 0311 head with a TUPY head
-Replaced head gasket (obviously)
-Replaced thermostat
-Replaced radiator
-Replaced radiator cap
-Replaced Temperature sensor on thermostat housing
-Replaced electric fan (was not working when I bought it)
-Flushed coolant system with radiator flush (twice)
Even after all of this it’s still randomly overheating, and after shut down boiling coolant spills into the overflow tank. To me it seems like potentially a coolant airlock issue or maybe even the head gasket is bad (although I literally just replaced it). I have bled the coolant system probably 6 times now, but the coolant will start to boil within 10 minutes of starting the vehicle.
Any ideas as to what I could be missing here? I’m pulling my hair out over this thing, I’ve damn near replaced the entire coolant system and it just won’t run. Thanks in advance for any suggestions!