Aux belt tensioner adjustment on AC Activa

andmcit · Unread post by **andmcit** » 12 Sep 2009, 19:56

OK, first time I've had to faff about with an engine that has this design of
tensioner with the AC pump - the car is the latest 99 V reg.

Least the tensioner arrangement looks like this!

The belt is squealing when cold and is not only is it really embarrassing I
worry about the aux belt letting go with disastrous consequences for the
timing belt and thus longevity of the engine - although it does seem to
settle down when the engine and belt are warmed up.

I did plan to take some play out by adjusting it and found the first problem!
It appears the design works on a basis of self adjustment against a spring
with no manual adjustment apparent. Does this mean the belt has stretched
and a new one is the answer as it looks to be in good shape but simply has
too much twist/loose play allowed on it - certainly well past 90 degrees
twist on the longest run?

There's no way of adjusting more slack out here?

Andrew

addo · Unread post by **addo** » 12 Sep 2009, 21:18

Andrew, you are correct in saying it's a self-adjuster.

Two things to check - firstly it must be removed with the locking pin fitted, else you must refit the tensioner alone, and "spring" it loose then fit the locking pin, then remove.

Secondly, purchase a new belt (service.citroen usually list the correct length, so don't rely on a third party's crossover book) and do the old "back to back" length check.

Can't speak of PSA product, but spring tensioner failure isn't something I've heard about or seen on some common names using similar approaches.

andmcit · Unread post by **andmcit** » 12 Sep 2009, 23:41

I guess because the belt looks quite fresh there's the real chance it's the
wrong length and I've only just bought the car although it wasn't screeching
when I first drove it.

I'll see about buying a genuine belt first and work on the basis that if it still
has too much play the tensioner isn't moving correctly to tension the belt
or could even have it's own issues!!

Cheers guys!

Andrew

addo · Unread post by **addo** » 13 Sep 2009, 03:04

Mike - it's always worth checking - may be longer (or shorter) by some significant amount, leading to a reasonable presumption of incorrectness!