Chevrolet Repair: no compression to number one cylinder, blown head gasket, chevy celebrity

Question
I know that you said you work on trucks, but I have a really quick question about my 1985 chevy celebrity.  It is a 4 cylider and I was told that I had no compression to the number one cylinder.  What can I do? It is something very serious? Should I be driving it?  Thank you for your time, sorry it is not a question about trucks.  I just need some great advice!

Answer
Hello D,
It could be a stuck valve, a broken valve spring, a valve with a piece of carbon holding it open, a burned valve, or a blown head gasket.
A hose connected to the spark plug hole, and compressed air blowing through it would be the way I would test it. With that cylinder at top dead center, compression stroke, when both valves should be sealed, listen for where the air is escaping.
Out the exhaust means the exhaust valve.
Out the intake means the intake valve.
And out the oil filler hole, or out of the radiator cap means a probable blown head gasket.
If it passes by one of the valves, removing the valve cover and checking the push rod clearance, and possibly wiggling and tapping on the valve could jar some carbon loose, or at least let you see where to concentrate.
A head removal and valve job could certainly be called for though, and if a piston happens to be burnt through, it would call for an overhaul or more.
Van