What happens to the engine in a 03 Cavalier if the timing belt beaks?

....well according to my sources, it has a timing chain. 2.2 liter?

The 2.2L Ecotec engine in a 2003 Cavalier uses a timing chain instead of a belt. When the chain breaks most likely there will be broken intake and exhaust valves, possibly holes punctured into some pistons, the timing chain cover may get a crack in it, and the oil pan may also become cracked or a hold punctured in it as well.

Good probability of bent valves. Sometimes it just marks the pistons. It depends on what the engine speed was when it failed. That's why I have a spare Ecotec head in the garage. The early (2002-2003) 2.2L ecotecs had a poor timing chain oiling system and they were prone to failure if the engine was run at high RPM's. Updating the oiling system is recommended if the chain is replaced. Change the water pump at the same time.

Part of the problem was sludge buildup from lack of a pcv valve which would block oil feed hole for tensioner. Doing an engine flush prior to a synthetic oil change helps greatly .

I heard rattling around the front of my 04 2.2 and it was just the serp belt tensioner that shattered within itself after replacing it no more problems at all 122k on motor oils clean as a whistle plugs looked real good when I changed em car runs like a new one

Chains have a tendency to rattle but with out the extra strain of pushrods I don't see how timing system can ever fail in stock application but there are writeups of the hydraulic chain tensioner failing due to crud built up and less than sufficient oil flow to the little hydraulic ram in the tensioner which would keep to chain slap and misalignment if timing all thing that can lead to catastrophic failure of valvetrain due to close tolerance interference design keep your ecotec oil clean to keep that little hole that feeds the tensioner its oil and keeps the chain tight and these motors probably will last 500k