Hey guys! New to the site, not new to the Jeep world! I just picked up a 99 cherokee, 4.0, 4x4, auto. I just bought this thing. When I looked @ it no ckeng light when I 1st started it, as it warmed up the light came on. I asked the owner about it and he said the light came on, he had it checked out and there was an evap leak, found a loose gas cap. I took it in and had it scanned, missfire #2. They did a compression test, 95psi, the other cylinders were around 165. I had them do a wet test, it jumped up to 175psi. The thing has 150k on it. Now, approx 3 weeks ago the small coolant hose above #2 broke and the thing overheated. I have a hard time believing that there may be a piston ring problem? My thought is a blown headgasket between the cylinders? There is no choclate milkshake, it doesn't smoke, no blow bye, oil had 2500 miles on it and it was clean.

Thoughts?????

Thanks Tye

 

Did you have leak-down test done?

 

If you have low compression on only one cylinder, and if the compression on that cylinder comes up when you put a teaspoon of oil in that cylinder and re-do the compression test, that points to a piston/ring issue on that cylinder, not a head gasket issue.

 

No leak down test. I'll probably have that done today when I get it home.

I really hope its not a ring problem. This is my 17yr olds 1st car and she's paid for most of it, so I'm don't wanna have to do a rebuild?

 

yep very true! and the leak down test will prove it for sure!

 

Found the problem! Blown headgasket! Did a block test and it failed instantly! Somewhere on the gasket its allowing the gases to mix with the coolant? I had a similar problem on one of my ol'******.