Head gasket or.......?

[d1981]

Hi All,
New to this forum so I apologize if this has been covered somewhere else. I searched but couldn't find an answer(I know, not an excuse).

Anyways, I just got a 89 4.0l cherokee and only three cylinders are firing. After doing a compression check this is what I got:

Cylinder - PSI
1 125
2 90
3 85
4 0
5 85
6 124

So my question is this: Is this a typical reading for a blown head gasket or does this indicate more trouble than just a bad gasket?

I'm also noticing that the engine heats up rather quickly and the overflow bottle boils over after a couple minutes of idling. There doesn't appear to be water in the crankcase and there isn't any white smoke from the tailpipe either.

[5-90]

Could be a head gasket, could be rings, could be a blown valve. Next step is to perform a leakdown test to isolate the problem.

A compression test is good for telling you there's a problem, but doesn't do a damn thing toward sorting it out...

5-90

[Dr. Dyno]

With low compression in cylinders 2, 3, and 5, and no compression at all in cylinder 4, you've got a serious enough problem that warrants pulling the head to find out what it is. Burnt valves could be one possibility, worn piston rings could be another, but cylinder 4 must have a hole in the piston.
Don't even bother with the leakdown test. Just pull the head.