i have a 07 cobalt 2.2 and for a few weeks was having a problem starting it also low idle and sounded real rough and loss of accleration power. then one morning it wouldnt start at all it sounded like no comprsion. i pushed it to my mechanic and he said the crank sensor was bad so he replaced it. then i get a call saying the engine is blown!!! he told me there was no comprsion and there was spark and fuel getting to the motor and valves and timimg chain where fine. does this sound correct ?? never had a engine blow without lots of oil everywhere or had it overheat. is it possible he is not looking for something or is there something he might not no? its a small gas station not a real mechanic shop?

 

the easiest way to find out is go on over there and have him show you with a compression tester while you are there. If he can't show you then ask him how he decided it has no compression.

 

Welcome to Cobalt land, Once you enter there's no escape

 

This.

 

And no compression in one cylinder doesn't necessarily mean junk motor. Often a single cylinder is fixable.

 

You might want to get an second opinion.

 

No compression could mean a number of different things, recommend a second opinion. If the valves are fine the next week link in the L61 is the ringland area, a boroscope would be able to tell you if they are destroyed. I dont know of anyone blowing through a cylinder wall on these engines (I'm assuming you're stock).