V6 TDi - Ribbed Belt Woes

[S2central.net]

Strange one today... the missus brings the allroad home - just a short journey where she noticed the steering go awfully heavy just at same time as battery lamp came on.

Dunno how she steered that tank home without PAS - she is a sturdy lass - nuff said.

Tells me the woes in the house and I immediately think ribbed belt as I remember it goes to both ALT and PAS pump... Idling in the driveway there is a slightly rubbery smell at the front of engine - and the viscous fan isnt moving either.

So either the belt has split (was brand new a few months ago) or the self-adjusting tensioner has gone south. The tensioner is original item (140k miles).

Changing the belt and/or tensioner is 15 mins work - except for the 90 minutes of dicking about to get undertray off, bumper off, into service position, snub mount off, aircon belt off, belt covers off and then I can see WTF is wrang wee it. Sorry - a wee bit of RabC sneaked oot there (by the waay).

Just when I thought that Allroad had enough spent on it recently. May as well change the engine oil at the same time.

[S2Roo]

Hi Paul,

Not sure if the tensioner is the same design as a 98 AFN 1.9 Tdi Passat, however if it is the spindle bends over time.

I replaced all the belts on mine and headed off to Southern Italy for a Holiday (180,000 mile car). Somewhere near lake Garda my auxiliary belt snapped. I managed to coax the car to a dealer (lots of down hills fortunately as you have no fan, water pump brake hydraulics etc. .) and bought a new belt thinking the one I had fitted was duff. I was then heading past Perguia when the new belt came off. I looked and the tensioner spindle was bent causing the belt to wear and come off. Long story short I had to chuck it into a main dealer to replace (which involves putting the car into the service position), 340 Euros later I was on my way. The auxiliary tensioner is not mentioned as a serviceable item, however the Italian dealer said they changed them every 60,000.

If I have not helped at least I have shared a miserable holiday story - on that trip I also got "fined" 250 Euros by the Garda for driving with my lights off during the day, and fined 300 Euros in Austria for not having a motorway ticket - I wasn't even supposed to be in Austria so had no idea - epic fail! DOH!

Heres a pic of the Passat tensioner if it helps.

[S2central.net]

The V6 tensioner is different, but its a candidate alright... I seem to recall it was a bit stiff to move when I was doing the rebuild a few months back. Cant remember if its a spring loaded thing or hydraulic affair - pretty sure its a spring and beefy looky thing too.

[TimE-J]

I dont know if this will help but I know the 1.9thi pd engines have a fault with the one way clutch in the alternator pulley (it seizes up) and this inturn causes the tensioner to vibrate more than usual causing it to wear rapidly. Just check that if you do have a one way clutch pulley then make sure its still working!

Whether this is the same with yours i dont know but I thought id give you the heads up just incase!

[s2avant]

As it's the V6 TDi and the tensioner is the original it's a fairly safe bet that the bushes (23) and seals (24) at the pivot point (21) have failed. Common as muck and once they are gone the tensioner drops causing the belt to run at an angle.



You'll need to check if anything else has worn out as a result though as it could get expensive.

Ben

[S2central.net]

Ahh good info Ben - cheers for that - deffo worth a close look.

[S2central.net]

I don't have pics, but stripped the patient today - and Ben was 100% on the money...

The front pivot bush (23 on his diagram) must have worn over time to the point that the pivot bracket was no longer centred on its mount - then the bush eventually disintegrated - I guess its a nylon kind of thing... The bolt (22) was actually sheared and so the tensioner bracket was just kind of dangling.

Obviously the belt got snagged in the mayhem and chewed itself to an early death.

I was a bit distraught at chances of getting the chewed bolt out of the housing... seeing as the radiator and aircon make it impossible to get a drill in there - so we dropped the whole front off - a mate had done it before on a V6 TDi Passat - there is enough flex on the aircon and PAS cooler pipes that you rotate the whole front section down towards the floor... Sure you have to dump the coolant, unplug some wires and disconnect the intercooler pipes but not much drama actually.

Then we could see properly and get in there with a drill if necessary to extract the remains of bolt. Luckily a little pick tool was able to spin out the bolt. I have to wait until Monday for parts which is a beeatch, but this is a poor design in my opinion... The service book should state this bush gets replaced with the ribbed belt.

Cost of bolts and bush + seal will be less than a tenner. Guess the new belt is 20 ish - but it is hours and hours of time to get things stripped this far back in order to effect a proper repair.

I was dead lucky this happened the car only about a mile from home.... The last big episode on the car was the camshaft failure and that was 500yds from home - what is that all about - not that I am complaining !

Thanks again Ben for helping on this.

[JP]

Check the aircon pump is tight too. I've seen loose ones strip the ribs of belts.

[S2central.net]

Funny - one bolt for the aircon pump bracket had fallen out, and another loose, when I rebuilt the heads last October... I removed it to gain access to EM bolts on that side and thought it really queer that engine vibrations would cause such a thing - just figured it had never been torque properly in zee factory. mmmmmmmm odd.