Volvo s40 2006 2.4i I was on the freeway the other day and the oil light came on and the car shut off immediately.I got it turned back to my house and I check the compression and all of the cylinders were about at 50 psi. Cylinder 3 was less than that. I changed the head gasket and it didn't do anything any advice on what I should do next? So I checked a PCV breather box and my diaphragm is punctured could that cause it not to start? I have a new one on the way

 

Your engine stopped running while driving, you now have 50psi or less compression on each cylinder, you changed the head gasket before or after that?

Either way the cylinders will not fire with less than 100 psi in compression. What is the compression now?

Pcv is not your problem.

I'd bet the cam timing changed and bent the valves -

 

next step is a leakdown to check the valves and then confirm the cam/VVT timing. When you changed the head gasket did you inspect/test the valves with the head off? Did you follow the correct procedure for resetting the VVT gear / cam timing or did you simply return it back to the original position?

 

I replaced the head gasket after the car broke down last week. I inspected the valves and they didn't appear to be bent. I even did the water drip test on all the valves and 3 and 4 had a very small dripp but nothing that bad.

 

A head gasket will not make the engine stop running (actually it will but the much more of the engine will be melted and destroyed by that point)

So what is your compression today?

 

50 psi in cylinders 1245 and 30 psi in number 3. Should I preform a leak down test?

 

I'm thinking there's nothing but pain ahead. Loss of oil pressure has done something spectacularly bad to the internals of your engine (rings - cylinder walls?).

You might get a borescope and take a look at one or more of your cylinder walls - I'm betting they're not pretty...

 

so the weird thing is the cylinder walls looked imaculate still and the engine turns over with no knocking sound. isnt that kind of a strange thing for a car with bad rings/ walls if its not knocking/

 

Your engine does not all of sudden have "bad rings" - either you have bent valves or the cam timing is off - hopefully it is just cam timing.