I was driving at 50mph and the engine shut down suddenly.
It doesn't crank when I turn the key. It only makes a slight whirring
sound. What could it be???

 

Either timing belt broke or you skipped a few teeth. Your looking at a large repair bill if thats the case

 

Thank you Cincy. Should the engine crank even with the bad timing chain
or did the computer shut the system down to protect the engine?

 

Which engine do you have? Both 2.8 and 1.8t have belts, not chains. What happens is you damage the valves and the compression goes to almost nothing so no compression, no fire.

 

yeah, we have interference engines so if the tb goes out, big bill...

 

It's a 1.8 turbo. Am I to assume the engine is also damaged??
Is there an on-line, step-by-step instructions for replacing belt?
Thanks guys for your prompt input!

 

there are guides to do the belt job, for instance this one...
http://www.audiworld.com/tech/eng35.shtml

but if that happened you will either need to be rebuilding your engine or replacing it. when the belt snaps you can bend valves (which almost always happens) damage valve guides, break connecting rods, punch a hole in your pistons, etc...

the whiring sound you hear is the starter spinning your crankshaft which has no compression to force against it so its spinning freely. is this a manual or auto transmission car?

just replacing the belt will not fix it unfortunately.

 

Thanks guys. So what you are telling me is the whirring sound is indicating damage done to the valves/rods etc.?

 

yeah most likely.

Josh

 

they are saying that but from the description we don't have enough evidence of it. For all we know your starter solenoid went out and isn't engaging it to the flywheel. Pull the timing belt cover off and inspect. If its obvious something happened like the belts frayed or broken then you have a big bill coming. Even if it doesn't show anything obvious it could have skipped a couple teeth and hit some valves. If there are no obvious signs do a compression test. If it reads low compression you have a problem if it reads good then further diagnosis is necessary. If it sounds like the start is spinning freely then tap the solenoid part w/ a hammer and try to crank over and over it might kick over eventually. That would mean you need a new starter. Although it does sound like a timing belt since it happened while driving and the starter would have to be a really weird coincidence.