300Tdi - "Squeak, The Return"

I haven't got around to trying it on mine yet. I was going to try and do it with the engine running and use a piece of wood with some fine wet and dry stapled to it so I can get into where the pulley is safely.

If the pulley is worn down so that the belt is sitting too far down the "V" de-glazing won't help much. You will need a new pulley shortly. Regards

It's the tensioner pulley that you deglaze. The flat side of the belt runs against it.

Simon Barr wrote in news:bvqidf$vn47n$ snipped-for-privacy@ID-113705.news.uni-berlin.de:

I did that briefly without the wood and the staples...then my nerve gave and I decided I had risked life and limb far enough for one squeak! Yes, the wood and staple idea sounds a better bet even with today's wonders in micro-surgery!

Derry

Try Graphite powder, for locks, from the local locksmiths .. A couple of small puffs and the squeak is gone. It comes back after a couple of weeks, but another puff and it's gone again. This process repeats a couple more times, but eventually, over maybe 12 weeks, the squeak goes and stays away.

A friend hypothesises that it's the flexibility of the belt that's the real issue and the graphite powder adds some suppleness and lubrication without making it slippery. I've certainly had no problems with it slipping since applying the powder.

Don't use too much. I did mine with the engine running and applied it to the inside and outside of the belt, without getting my hands or fingers anywhere near anything remotely dangerous - the plastic puffer bottle has a

G'day Derry..

I've had a 110 300TDi for six years now. For the first year or so I, too, wrestled with the belt 'squeak'... ( had alternators, pumps, pulleys etc checked out, too. It _was_ the belt!!.. Then I used 'pure silicone' ( the stuff I bought is made by Toshiba, but others will make it). It's used, amongst many other uses, as a 'release' agent in plastics extrusion. Gees.. It's almost impossible to get the last traces off your fingers with _sandsoap_ and no solvents I have will remove it. This stuff _stays_ !!

_No squeaks_ for years !!!

Sanding, soaping etc _didn't work_ for more than a week or so..... but this 'pure silicone' ( it's perfecly clear and about the consistency of honey.. and , most importantly, _inert_) _works_.. _long term_ . Guaranteed !!! :))

.... frodo.

snipped-for-privacy@nothankyou.mam.inOz (frodo) wrote in news:spamity-spam-bam- snipped-for-privacy@1cust199.tnt.gosford.au.da.uu.net:

OK, I'll try anything...have been enquiring the price of a new engine...but maybe that's getting a bit drastic..

Derry

"Paul - xxx" wrote in news:bvrtim$se1g2$ snipped-for-privacy@ID-137265.news.uni-berlin.de:

There can surely be no issues with a ribbed belt slipping?? Though I accept that the squeak may come from sideways movement of the belt on the tensioner.

As another poster has pointed out, it is the flat back of the belt that bears on the tensioner and all indications are that this is where the squeak comes from, though more rarely (possibly) from the cam shaft pulley area.

Is there an engineering newsgroup where this might be explained?

Incidentally, the squeak HAS diminshed since I gave the tensioner pulley a rub with emery paper and I will give that another go as soon as time permits. But it still squeaks! Can't find pure silicon anywhere.

Derry

Just don't get it on any electrical contacts. The slight spark of the contacts opening will break down the silicone and deposit silicon oxides on the metal.

I've got some of this at home so I think I'll try this as well as wet and dry on the tensioner pulley. Its quite cheap as well, think I paid a couple of quid for the bottle I've got.

I just used chalk this morning. Engine running, stick of chalk drawn over the outside & the inside of the belt, no squeak. For now. I had hoped that replacing the belt would solve the problem (the old one was beginning to give up the ghost), but it came back again.

The downside is the dusting of pink chalk over the rad hoses...

I've deglased the tensioner wheel already using a small stone file, so that isn't an issue.

Oh - and the Haynes manual is likely to go in the bin sometime soon. "Unbolt the upper fan cowling" indeed - the fan cowling is a one-piece moulding. Gits. At least the belt was fairly easy to manoeuvre over the fan blades.

Peter

I spoke to the technical manager of the belt manufacturer again today and quizzed him WHY the 300Tdi belt should squeak and why it was so difficult to cure.

His reply is that the belt and tensioner pulley get glazed and produce the squeak. It is the same effect as when you pull your finger down a sheet of glass. Or rub your wetted finger lightly round the rim of a wine glass to produce a humming noise. That is why the "de-glazing" of the tensioner pulley works. In effect, it changes the frequency of the vibrations and sound is caused by vibrations. Sounds sensible to me.

As an alternative, he suggested using resin (as used by violinists -- another example of vibrations creating sound) on the tensioner pully as this would also change the harmonics and get rid of the squeak.

This is all beginning to fall into place. There is a related problem in Land Rovers with squealing brakes. Put an absorbant pad or some Copper-eaze (or mastic, etc) behind the brake pad and (in theory) the squeal disappears.

I de-glazed the pulley again today by holding a piece of emery paper against it with the engine running and the squeak has again gone. It will be interesting to see for how long!

I think the above explanation deals with all the suggestions so far though I suspect belt alignment probably has something to do with it as well. Almost impossible to eliminate all movement at the tensioner pulley because of engine movement of course. This has been an interesting problem that I suspect will have to be deal with regularly along with all the other periodic maintenance jobs.

Derry

Hi all,

We have a 200 & a 300tdi and found by fitting a Gaites power grip belt we never have any problems with squeaks for the past few years.