Loose timming belt

[DaveVoorhis]

Did you do the timing belt and tensioner change yourself?

[DaveVoorhis]

If a new belt is loose, I would suspect the tension was set incorrectly when the belt was replaced.

[nariusb]

Ok , so My 1989 525i with m20 engine is at the mechanics. It went in with oil leak. It was a valve gasket. He just called and says the timing belt is very loose, come take a look at it. Now the belt and tensioner was done about 50 miles ago so I can't see it loosening like that? The car has no drive ability symptoms.
Should I go with another timing belt change? What would cause this?

[nariusb]

No, mechanic friend did it and I was present. I know the parts were new - I bought them myself.
Is it possible for the belt to loosen up like that and what would be symptoms? I never delt with this particular garage but they come recommended.

[Blitzkrieg Bob]

Have the mechanic rotate the crank clockwise and see if the timing marks line up on the cam & crank.

If so, he may just need to reset the tensioner.

[gmannino]

This is why I always do everything myself. Timing belt change with the bentley manual is very doable for your average DIY person.

[nariusb]

Have the mechanic rotate the crank clockwise and see if the timing marks line up on the cam & crank.

If so, he may just need to reset the tensioner.

Thanks Blitzkrieg Bob,
Can I actually see the marks without taking anything apart? If so where do I exactly look for them?
Is reseting the tensioner just compressing and releasing the spring?

[billy]

Thanks Blitzkrieg Bob,
Can I actually see the marks without taking anything apart? If so where do I exactly look for them?
Is reseting the tensioner just compressing and releasing the spring?

to see the upper timing mark you need to remove the upper timing belt cover and to do this you need to remove a few components, from memory that would be the distributor and the alternator support bracket.
It MAY be possible to do it without doing this because the mark on the cam is visible right through the tooth, so if you just release the top 2 securing bolts on the cover you may just be able to push it forward enough to see the tooth mark, i dont know ive only ever done it by having everything removed.
the tooth shoudl line up with a similar line on the cylinder head at about 1 to 2 oclock
The lower timing mark is visible, however you may find it easier to first remove the radiator shroud.
Remember that the lower pully rotates twice for every one of the cam, therefore if you are setting the lower mark first it may take another revolution to make the 2 line up.
to reset the tensioner depends if the spring is still present, many loose it over the life of the car, if its there then simply release, not remove, the 2 securing bolts and the tensioner should pop to the correct tension, if the spring is missing you will have to manually push the tensioner until you get the correct tension.

[nariusb]

to see the upper timing mark you need to remove the upper timing belt cover and to do this you need to remove a few components, from memory that would be the distributor and the alternator support bracket.
It MAY be possible to do it without doing this because the mark on the cam is visible right through the tooth, so if you just release the top 2 securing bolts on the cover you may just be able to push it forward enough to see the tooth mark, i dont know ive only ever done it by having everything removed.
the tooth shoudl line up with a similar line on the cylinder head at about 1 to 2 oclock
The lower timing mark is visible, however you may find it easier to first remove the radiator shroud.
Remember that the lower pully rotates twice for every one of the cam, therefore if you are setting the lower mark first it may take another revolution to make the 2 line up.
to reset the tensioner depends if the spring is still present, many loose it over the life of the car, if its there then simply release, not remove, the 2 securing bolts and the tensioner should pop to the correct tension, if the spring is missing you will have to manually push the tensioner unt
il you get the correct tension.

Thanks very much,
It was a tensioner bearing gone and it was loose big time. So another belt and tensioner change. I bought it at bavauto, I wonder if it was made in China?