Broken timing belt and engine compression

GCHAPPELL

MEMBER
2005 CHRYSLER PT CRUISER
2.4L
4 CYL
AUTOMATIC
150,000 MILES

I have the basic (not turbo) model. While driving down the highway it made a noise and stalled and would not start. I had it towed to a mechanic who said it was a broken timing belt but later (before replacing the timing belt) he said he thought it had engine damage because he could get no compression from two cylinders.
I did not think you could get any compression if the timing belt was broken because the camshaft cannot rotate. Is it possible to test the compression if the timing belt is broken? Also, how do I know if I have an interference or a non-interference engine?

3 Replies

STEVE W.

MECHANIC
13,465 POSTS

You can test for leak down with a broken belt which is what he probably did. You could just ask him what he did.

The 2.4 is a non-interference engine but there is a catch. Because of the design of the valves it is possible for them to hit each other if they were to get out of time. So if the belt started shedding teeth and the valve timing slipped it is possible to have valve damage. It is also possible that the engine has carbon build up. The clearance the valves have is very small, so if it had a bunch of carbon built up it could cause the pistons to hit the valves.