engine knocking noise

[C-mann 0]

Seem to be having yet another problem with my VR6. When the car accelerating or idling there’s a constant knocking noise coming from the driver’s side of the engine. At first I thought the alignment of one of the belts was out or that a bearing had gone, but no nothing that simple.

 

Can anyone shed any light on this matter before I put it into a garage and get charged a small fortune?

[dr_mat 0]

How many miles on it?

Does the knocking change with revs?

You've checked the belt then?

You've checked your engine mounts?

[C-mann 0]

The C has done about 129000 miles. It’s more like a constant tick; tick, ticking noise than a knocking. When you push down on the accelerator the noise is there but when you take your foot off the pedal it goes. Even when idling.

[dr_mat 0]

Most likely it's the tappets or the timing chains..

If it gets worse when you hold the engine at 1200rpm, it's most likely the timing chains (for some resonance reason I presume), but if not, it's most likely the tappets.

How bad is it? I mean, really bad tappets will start to cause misfires when cold and stuff.

They are never silent, by the way...

[C-mann 0]

Just been informed by someone its more likely to be the tappets. It has to be the most annoying sound ever though.Been told that a thicker grade oil could reduce the noise. Whats recommended??

[dr_mat 0]

Actually, a thinner grade oil might help too.. The basic issue is that the tappet is probably a little blocked up, so it's difficult to pressurise with oil. Thinner oil will enter the tappet more easily, and may help. You might also try some Wynns Hydraulic Lifter concentrate from Halfords, this might free it up a little.

If the tappet is releasing pressure too easily, however, then maybe a thicker oil might help too, but it all depends...

[Kevin Bacon 5]

Noisy tappets are noisy because they're worn and at 129,000 miles, they are almost 50K past their effective service life. You can try thicker oil but the only cure is to replace them, they're only about fiver each from G&S and a couple of hours work.

 

K

[dr_mat 0]

Vince quoted me £254 to do the tappets on my VR!!

And that was *while* the manifold and cam cover were off for the timing chains!

[C-mann 0]

Thanks for the help!!

 

Its gave me something to think about.

[C-mann 0]

Thanks for the help!!

 

Its gave me something to think about.

Finally got a price on parts and labour after a garage quoted me £450+vat for replacing the tappets. I nearly died of shock so did some hunting around. The parts come to £101 i.e. 12 tappets, upper timing chain, oil filter and 2 rocker gaskets. The labour still comes to £200 and that’s a homer, but its still a saving of £150.

 

Hope this web site can help anyone else.

http://www.vwspares.co.uk/delivery.html

[dr_mat 0]

Lot of labour involved with replacing the timing chain. You have to drop the gearbox off to get the lower cover off so you can drop the chain off the sprockets. If you're doing the timing chains, you MUST replace the tensioners and guide rails at the same time. The chains don't wear, it's the guides and tensioners that wear.

[C-mann 0]

In that case I think I'll leave the chain as it is!!

 

Are they classed as upper/ lower guides and tensioners?

[dr_mat 0]

Please will a mod make this post go away? It was a dup of the one below.

Ta! :)

[dr_mat 0]

Indeed they are. There are two upper chains too - both run in the same guide and tensioner though.

The lower guide/tensioner are completely obscured by the lower cover, so you can't even inspect them without taking the g/b off. But from what I've heard, they very very rarely wear out - it's pretty much always the upper tensioner that goes.

Sorry, should add - you can replace the upper guide rail without taking the g/b off, but not the tensioner.

[C-mann 0]

So what your saying is that I need to order two upper chains and one upper guide rail??

[dr_mat 0]

Nah. If you're in there, check the condition of the upper guide rail. You can't replace the upper chains (either of them) without dropping the gearbox.

But if your guide rail is knacked, and the tensioner is ok, then it's worth replacing the guide rail, which can be done simply enough.

What I'm saying is that if you *do* try and replace the "upper chain" you need to ask the guy at VW for TWO upper chains, or make sure that the part number you order contains TWO chains.

But you already said you don't wanna do that, so...

Clearer? ;)

[C-mann 0]

I think thats me happy now!

 

Cheers for the help!!