2.5 TD Belt Tensioner Issue

[Scatmancraig]

Yet another problem has surfaced on my 2.5 TD....

Just lately, the auxiliary belt tensioner has a habit of un-tensioning itself, usually when the engine is switched off.  A firm tug on it brings it back into place, and it's fine when running normally.  My car has a habit of stalling when cold, and the engine suddenly stopping under load usually triggers the fault.  When the engine stops, there is also a horrible screech that seems to come from the tensioner assembly.

This was never a problem until I changed the water pump a couple of weeks ago.  During this procedure, I used a big bar to release the tension against the spring so I could get the belt off.

Have I broken the tensioner or have I missed something?  There is a recess on the front of the tensioner pulley which I have a correct sized tool for, I've tried doing this up tight or leaving it slack, and it seems to make no difference to the fault.  When driving normally, it is fine and the tensioner stays against the spring.

Any ideas on what might be wrong?

[TheBoy]

Undo top of tensioner (use method I wrote in the guides, else you run risk of snapping the weak casting by using prys).  Remove belt. Check the L shaped arm is free to pivot easily, and check tensioner/damper still has a lot of spring strength.

[Scatmancraig]

I've found this one?

http://www.omegaowners.com/forum/index.php?topic=90622.0

I did a search but couldn't find one by your good self?

[TheBoy]

That'll do. They're my pics, I think Shack tidied up the thread

[Omegatoy]

the pivot tends to sieze as its not lubricated, I did mine once and it sorted it for good used himelting point grease if i remember

[Scatmancraig]

I completely removed the whole assembly. The L-shaped bracket pivots fine, and there seems to be a lot of springiness in the damper unit. I reassembled it all and still no different. Enough tension to keep the tension with the engine running, but if it's cold, and the engine stalls, it pings it off tension. And it also makes a nasty noise when you switch the engine off.

[TheBoy]

I'd still suspect tensioner assembly.

Its possible the belt is too long I guess, but the fact that its tensioned when engine is running makes me think its still tensioner...

[Scatmancraig]

I'd still suspect tensioner assembly.

Its possible the belt is too long I guess, but the fact that its tensioned when engine is running makes me think its still tensioner...

Its fine normal running. And was never a problem at all before I changed the water pump. I think that I must have damaged the tensioner slightly during that procedure.