metallic tapping noise axe engine

[tossman]

I have a confusing issue with my 2006 128kw auto.
Bit over a year ago I notice a tapping/rattling noise from the engine at idle.
I assumed it was the camshaft worn out so figured it would need to be replaced when it got hard to start , Ran rough or the noise got worse.
Well the noise didn't get worse, in fact after giving the engine a degrease and a wash with the hose, The noise actually stopped !Well for a bit anyway.... The moment I started it after its bath I noticed the engine was quiet.
Anyway this was a couple of weeks ago and since then the noise comes and goes, sometimes its there when started, Other times its not, but after idling for a few minutes you can hear it build up and return .
The vehicle has done 280k so I wasn't surprised for it to be the cam... but now im not so sure.
It still goes like a train, I still get over 900km out of a tank.....

Interested to hear if anybody else has had this happen

Mark

[Umai Naa!!]

Does it smell sooty?

A metalic noise is often mistaken for a cracked exhaust manifold at #1 cylinder.

Also worth checking the condition of the water pump, by removing the inspection cover and seeing how much play there is in the gear.

[Sunny43.5]

We had a similar noise with our T5 turned out the bearing in the air con compressor was failing > VW dealer thought it might have been camshaft problem but in the end it was the bearing and it had also caused the mounting bracket to crack and fail , $1600 for repairs as they will only replace the whole compressor , seems dumb to me to have to replace a major part for the sake of a $40 bearing . But from what I have read VW need the old parts back so THEY can recondition them and then sell them back to customers as VW rebuilt parts . This is why VW will charge you extra for a metal component part if you do not give them the old one back , I think this system is wrong very wrong as when you buy the van new you own it lock stock and all parts , if VW want the old ones back they should be paying US for the part not vice versa IMO.

[Umai Naa!!]

You get a decent discount on exchange parts.

[tossman]

how long did you have the noise for in the air con compressor ?
its actually hard to tell where its coming from, its just there !
it doesn't change with air con on or off, I originally thought it may have been the gates couplings so I changed them when It first started.
I think the manifold could have a crack or two. It does smell on start up, no major soot spots that I can see though.

[Umai Naa!!]

In and around the brake master cylinder and on the firewall will be black with soot.

[tossman]

No, its pretty clean. I have read in other posts about "the black soot" so have been fully expecting to see it...
There is a bit of oily black goop down behind the turbo, but I can see its coming from the outlet connection of the compressor, one of the lugs on the connecter has worn away and taken some of the wire clip with it.
One of those alloy forge motorsports couplers will sort that.
I looked into trading the vehicle last week and the used car dude at the dealers reported back that it needs a vacuum pump and its down in the bowls of the engine and will cost a bit over a grand.
Yeh right, he knows what he's talking about. I didn't bother pointing out the dual pump.

[Umai Naa!!]

The vacuum pumps on them are generally ok.

You'll know it's failed when you get a fuel sample that's black.

If anything, it'll be the gasket that's leaking. They're only about $60 or so, and about half hour to replace.

[Sunny43.5]

You get a decent discount on exchange parts.

Not at my local VW dealer they quote the parts price and then tell you there is a refundable amount on top of that they will give you once the old one is returned No mention if it being a discounted price . Or do you mean that the reco parts are discounted ?? as opposed to new parts .

[Umai Naa!!]

They're charging you the outright price, and refunding you the difference when you return the old part.

Which they're entitled to do. Otherwise, if you don't bring the old part back, THEY have to wear the difference, or try and chase you up for it.