Ok, I know these has been probably beat to death, but I have been searching for a couple days and cannot get a definite answer. So.....

89 XJ, 4.0 Auto, 160K -- Overheated on the way home, needle was in the red prob around 250. Got it home, added some coolant since it was low. BTW, at some time the cooling system has been converted since I do have a radiator cap. Drive it the next day 20 miles to work and gets hot again. Started getting a little sluggish taking off. Parked at work and it was gurgling in the overflow tank...but the radiator cap was barely warm. Replace t-stat and drove up and down the road and temps pegged at 260. Once again it was gurgling but the cap was cool. Added more coolant and now its puffing white smoke/steam from tail pipe. Coolant and oil look fine. Today I tried to check compression. I know you are supposed to test it warm, but I did a cold test. The highest reading I got was around 110psi with the lowest begin just under 90psi.
Questions are:
1. Is the head gasket gone?
2. Are the low compression readings just because it was a cold test?
3. If its just a head gasket, are there any foreseeable problems with bottom end of the motor if I put on a new head gasket?

Sorry if this is basic stuff, I'm just really frustrated and not exactly sure where to start. This is my DD and I need to get it back on the road....and I don't want to do all the work for the head gasket if its gonna tear the bottom end up.

Thanks for the help

 

Head gasket blown into cooling jacket, thereby pressurizing the system almost immediately.

If the oil pressure is still what it was before, pull the head and see how the gasket looks. Have the head checked for cracks before reinstalling. Check your ring groove and cylinder walls while you can see them.

Good luck.

 

Thanks....kinda the direction I'm heading. Considering a full engine swap now...came across a possible good deal on a complete '96 motor.