1996 BMW 318Ti Belt Drive

JORDANPARKER1986

MEMBER
1996 BMW 318
4 CYL
2WD
MANUAL
170,000 MILES

I have a 1996 BMW 318ti and would like to know what the cause is to a continuous screeching sound when the car is running. The drive belt is in good condition with no wear and I'm fairly certain that it has to do with either the idler pulley or the tensioner pulley. I'm a rookie mechanic and would like to find out if either pulley is worn out (and how much work is involved to check/replace) or if it may be something else causing the issue? Please help and thanks in advance :)

1 Reply

JACOBANDNICKOLAS

MECHANIC
108,133 POSTS

To check if it is the belt, try this simple test. With the engine running, pour a small amount of water on the belt to see if the sound changes. If it does, the belt is the problem. Next, you are correct in saying it could be the idler or tensionier. First check to see if the belt is tight. It shouldn't have much more than 3/4 of an inch play (before the tensionier moves). If it is excessive, replace the tensionier. If it is tight, remove the belt and check all accessories to make sure the spin freely, including the idler pulley.

Let me know what you find.
Joe