1991 Jetta

my dad has a 91 Jetta 1.8 Wolfsburg. When you go to start it.. sometimes it makes this incredibly loud sound, and you have to return the key to the off position, and then try again. Sometimes it only does it once, sometimes more, and sometimes not at all. Cold or hot. We haven't noticed a pattern to it. They replaced the starter in attempt to fix this, but it wasn't that. Its more of an annoyance rather than a problem. Anyone have any input, its appreciated.

It sounds like the starter gear isn't engaging the flywheel. I take it that is doesn't crank when this happens. Is this manual? Make sure they replaced the starter's bushing that's pressed into the transmission housing & have the flywheel gear teeth looked at.

its an automatic.. the sound you hear, isnt that it just doesn't turn over.. its a LOUD grind-like sound. The mechanic is my dad's good friend, and he was present, so im sure they did it correctly, or would have noticed anything. Both are just stumped at this problem.

What I was asking is does the engine physically spin when you engage the starter and it makes this noise, or does the starter turn and grind & the engine does not turn. Since you replaced the starter I don't think it's a bad bendix gear, but I do think it is not engaging the flywheel because some teeth on the flywheel have been damaged. That would explain why it only does it some of the time, if the engine stops on the bad spot it will grind. Automatics don't use a bushing in the transmission housing so it can't be that.

Im almost positive the engine doesn't spin when this happens, the car isn't trying to start, its just this noise.. so i'll check it out about the flywheel and such.