no compression on 2 cylinders

[DieselYJ]

I did a compression test on my rough running 1990 6.2 last night. No compression on the first 2 cylinders on the drivers side.
What could be wrong??
Head gasket blown between the 2 cylinders??
any other ideas??

Thanks in advance.

[AndyL]

That would be my first guess as well. You could remove both GPs and force air into one cylinder and see if it comes out the other.

[DieselYJ]

Hah, I never thought of doing that. I thought i would just put one of the glow plugs back in and then do the compression test, but your idea sounds better!!!