Q and A: Snapped timing belt can cause annoyance or catastrophe
QUESTION: I hope you can explain an engine issue and tell me if I got ripped off. Two years ago the timing belt in my Dodge Neon broke. The mechanic told me the engine was ruined, and I ended up selling the car for junk because I couldn't afford ...
QUESTION: I hope you can explain an engine issue and tell me if I got ripped off. Two years ago the timing belt in my Dodge Neon broke. The mechanic told me the engine was ruined, and I ended up selling the car for junk because I couldn't afford the repair. Last week the timing belt in a co-worker's car broke, and it only cost her $300 to fix. Why?
--R.J., Orlando, Fla.
ANSWER: First, a little background: The piston in an engine's cylinder goes up and down. Above the piston, valves open and close to let fuel and air in, and let burned exhaust gas out. The timing belt makes sure those valves open and close at just the right time. (A lot of vehicles have timing chains instead of belts. Belts are cheaper to build and quieter, and while the chains may need adjusting, they seldom break.) What happened to your Neon is that when the belt broke, the valves were no longer opening and closing when they should, and the pistons hit the valves, which can ruin the valves, the pistons and the walls of the cylinders.
Some engines, like the one in your Neon, are called "interference" engines, meaning the valves interfere with the pistons when the belt breaks. Your co-worker's engine was likely a "non-interference" engine, which is designed so the valves are far enough from the pistons to where they don't smash into each other if the belt breaks.
With either engine, change the timing belt when your manual says you should, be it 60,000 or 100,000 miles or whatever. If it breaks, at the best, you will be stranded and faced with a towing and repair bill. At worst, your engine will be damaged to the point where it may not be worth fixing.