Play in aux belt tensioner TDI

[rabbituk]

I've just had my idler pulley fall off today on my TDI and have ordered a replacement from a local motor factors to get the car back on the road as I'm currently 5 hours away from home and have limited tools with me. Whilst looking at what I need to do, I noticed that there is a little bit of play in the tensioner pulley and wondered if that should be replaced when I get home. Should I organise a replacment?

Here is a blurry video, the sound is the important bit.

https://photos.app.goo.gl/SKiR43awRZtf2otz5


Here is a photo of the pulleys showing the failed idler pulley.

https://photos.app.goo.gl/b7NHJ2LAuYAhsRSf6

[Martin Cox]

The pulleys comprise two pressed steel flanges with a bog-standard bearing sandwiched between them. It's perfectly possible to repair them by drilling out the rivets and separating the flanges, removing the bearing and replacing it with a new one. Just be careful not to distort the flanges when dismantling. Any bearing specialist should be able to supply a suitable replacement.

However if you do this, the bearing should be held in place with threadlocking compound or it can fret in the flanges and fail. The rivets can be replaced with suitable nuts and bolts, ideally locknuts or secured with threadlocking compound.

I did mine six years ago when the bearings showed signs of roughness and they've been fine ever since. A lot cheaper than replacing the entire pulley.

Martin

1998 V70 Tdi Auto

[Clan]

Originally Posted by rabbituk

I've just had my idler pulley fall off today on my TDI and have ordered a replacement from a local motor factors to get the car back on the road as I'm currently 5 hours away from home and have limited tools with me. Whilst looking at what I need to do, I noticed that there is a little bit of play in the tensioner pulley and wondered if that should be replaced when I get home. Should I organise a replacment?

Here is a blurry video, the sound is the important bit.

https://photos.app.goo.gl/SKiR43awRZtf2otz5


Here is a photo of the pulleys showing the failed idler pulley.

https://photos.app.goo.gl/b7NHJ2LAuYAhsRSf6

There is usually a touch of play in this type of bearing it allows the bearing room to self centre with the belt or it would tend to run off centre if no play at all. Rotational smoothness is the important factor.

[rabbituk]

I would have considered replacing just the bearing if it weren't for the fact that I am tight on time and don't want to be playing with cars this week. Without the car I'm reliant on public transport/taxis. Using public transport around here would mean and it would be a 2 hour round trip to the builders merchant every time I needed something for the property renovation I'm doing this week which would be a nightmare - prefer to see things in person. Have now replaced the belt, struggled a little bit to get it on as it is extremely tight even with the tensioner completely eased off. Tried sticking the belt in hot water, made no difference. However once I started turning the power steering pump pulley towards the tensioner the belt started to work itself onto the pulley. Incidentally I notice that ECP sell differing belt lengths for TDI cars with AC. One is 1685mm and the other 1795mm. I guess I must have the shorter one.

Will replace the tensioner pulley bearing with the method you recommend when I'm home and have more time & tools at hand. The crankshaft TVD pulley has a lot of lateral movement and there seems to be a small oil leak underneath there - nothing major as I don't need to top up between oil changes. But will look at that too when I have the car on the ramps at home. For a few years I have noticed quite a lot of vibration at idle. I replaced the upper rear engine mount which reduced the cabin vibration but did not eliminate it.

Thanks for your help.

[Martin Cox]

If the crankshaft TVD pulley (presumably you mean the big pulley on the crankshaft that drives the aux belt) is showing lateral movement, the rubber is probably near the point of failing.

If it does so, the outcome is likely to be spectacular and expensive. I'd suggest it be investigated as a matter of urgency. I think Volvo have now discontinued them but there are aftermarket alternatives. It's possible they may still be available from VW/Audi.

Martin

[rabbituk]

Yes that is the pulley that I mean. Here is a 3MB video showing the extent of the wobble on that pulley.

https://photos.app.goo.gl/zGHLMeGM2sKft2WA6

[Martin Cox]

That does not look at all good to me. I'm hoping some of the Tdi experts on this forum will also offer their opinions. For what it's worth I'd say replace asap.

Martin

[rabbituk]

The engine has 380K miles on it so things like the crank shaft condition are a little bit of a concern. As mentioned in the original post, there is a tiny oil leak near the crank shaft pulley so I wonder if the crank shaft seal is also not good. We've always kept on top of oil changes and do them roughly every 5k or 10k miles.

[Martin Cox]

If you've been servicing it regularly with regular oil and filter changes, I wouldn't be overly concerned about 380k. With a modicum of care, these engines are extremely durable.

I don't think it's too difficult to replace the crankshaft seal when the pulley is off so it would make sense to do it at the same time if necessary.

Mine weeps oil slightly from the sump gasket but it's so little, there's no perceptible drop in oil level between services. it's a little messy but it's not finding its way onto the belts so I've stopped worrying about it.

I've never heard of a Tdi engine with bottom end problems, apart from one which was in an extreme state of tune and the oil pump failed.

What usually kills them is broken cambelts and even then the pistons and the bottom end usually survive.

If you are getting the work done, find someone who really knows these engines; there are a few pitfalls for the unwary. If you are doing it yourself, there is a lot of helpful information on this forum should you need it.

Martin

[brickman]

Stop driving it immediately. Go back and review all the relavent previous posts on cam belt changes.

You can get the damper from heritage vw or I think brickwerks also do it. Febi bilstein still make them. Find the febi part number off one of those sites and then you can sometimes get it on amazon foe around £50-70 delivered and it's genuine (no one bothers to fake stuff for these old cars really).

You also need new crank bolt and diamond washer. You will also need 3/4" breaker bar, 1' extension and socket foe the bolt (27mm?) and a jack stand to support it. You basically can't do this job with only 1/2" socketry.

Is worth doing cam belt if its been 80k or 5 years. If its way under that then maybe just do crank damper and the bolt and washer as doing cam belt is not a super easy job.

These cars are worth keeping running as nothing newer that's really any more reliable. Source: replaced my v70 tdi 4x in the past 10 years and all of the replacements have died and then been re replaced with the old v70 again!