ok so i was driving my car to go put gas in it and when i went to restart the car it wouldnt go faster then 20-25mph.i checked the oil and there was none but the motor wasnt knocking.this is my girlfriends car so she never checked anything lol.i took it to my mechanic and
#1cyl 25psi
#2cyl 40psi
#3cyl 40psi
#4cyl 50psi
my mechanic told me the motor is done but someone else told me it needs a head gasket but the oil and antifreeze werent mixing.whats the problem?also a engine light came on and it read that i needed a crank sensor and i replaced it but at that point the motor was already running bad.what should i do?

 

Woah...those are pretty low. If she's ran without oil or even low on oil for a period of time I'd suggest to look for a replacement. Yes, you could replace the head gasket. But I would be concerned with everything else oil related. Bearings, journals, etc.

Couple questions,
What was on the DIC?
Any other codes besides the crank sensor?
Mileage?

My head gasket blew and I was hitting temps of 250* but never had oil and coolant mixing. It also ran fine. Never checked compression, the guides for my timing chain broke so the timing was off also. It never went into "limp" mode. Which is what I'm assuming you're describing not being able to go over 20-25.

 

Sounds kinda like a valve train issue.

CELs don't read anything. They give you a number and a title that rarely has anything to do with the problem.

I am taking a wild guess that it was P0016. That means your timing chain is getting bad, not that either the crank sensor or the cam sensor is bad.

 

Are you fixing it, or selling it, I see you have another thread started, but you didn't post an asking price.
A donor engine would be best or if you really love the car a ZZP or GM long block would cure the low compression!

 

The root cause sounds like it likely is related to your previous thread about it overheating - https://www.chevyhhr.net/forums/prob...se-help-47189/