* Interference Engine: If the PT Cruiser's engine is an interference engine (most are), a broken timing belt will cause the pistons and valves to collide. This will almost certainly bend or break the valves, requiring their replacement. You'll also likely need other repairs due to the damage.
* Non-Interference Engine: In a non-interference engine, the pistons and valves are designed so they won't collide even if the timing belt breaks. In this case, valve replacement wouldn't be necessary. However, it's still a significant problem requiring timing belt and potentially other related component replacement.
The 2006 Chrysler PT Cruiser used several different engines. You must determine which engine is in your specific vehicle to know for certain whether it's interference or non-interference. The engine code (often found on a sticker under the hood or in the owner's manual) will help you find this information online. Once you know the engine code, search online for "[Your Engine Code] interference engine" to find the answer.
In short: Assume it's an interference engine and prepare for potential valve damage. Don't attempt to start the car with a broken timing belt, as this will almost certainly guarantee valve damage if it's an interference engine. Have a qualified mechanic diagnose the problem.
