Rattle noise from Engine bay area

[Mc-BigE]

Hi all,
Just got me car back from a very expensive full service (incl. timing belt, tensioners, w.pump, alternator, aux belt, repaired rad. However the real reason for doing all this was to try to pin point the source of a tinny rattle noise only while accelerating hard , there is no rattle at 800rpm. My mechanic striped the front back to timing belt area, and removed drivers side exhaust down pipe to inspect the heat shield , which is renowned for going in early S4's (so have read on this forum). the passengers heat shield has already been removed at an early stage by 1 of the 2 previous owners. My mechanic assures me that the drivers heat shield is perfect, all CAT's are perfect, front of engine is perfect, turbos are ok ( has spent hours looking for the source of rattle and the only thing left , according to him, is to strip down the two heads and examine the cam chains, serious wallet haemorrhage! on top of the already expensive service.

I am going to examine the drivers heat shield again , might try to remove it, if I can ( read somewhere on www.s4biturbo.com about doing this)

Before i look into this, has anyone come across this before , i thought that the cam chains where to last the life of the engine, mileage is certified at 66K.
just to recap the noise sounds like a light tinny metal rattle only on acceleration it seems to be coming from back of drivers side of engine also can hear it from underneath drivers side. sometime sounds like gurgling!
as well as a rattle.


All suggests are welcome (apart from selling it! , for now.......)

[gavsteryoung]

I can here that noise on mine, if I find a road with a wall next to it then under WOT I can here a rattle.... was worried about it a year ago but a year on, all is still well.......

I dont hear it when the windows are shut and I dont here it if its an open bit of road......

there has to be something for the sound to bounce off..... and I need the windows down obviously....

I do get a different type of rattle if I put the car in 6th gear and excellarate from 900rpm until about 2000rpm but there must be a lot of vibration caused by the strain on the engine and drive train....

[Mc-BigE]

The rattle is quiet noticeable outside the car , but with the windows up the car sounds great!.

There are very little specialist S4 garages in Southern Ireland, so as a last resort , i'm thinking of driving to Wales for a Weekend Short Break, and maybe go to a specialist how knows S4 inside out. Can anyone recommend a garage in South Wales?

[SimonS4MTM]

If it is the chains then you will be looking at an expensive bill if they fail. If you cannot pinpoint the source of the noise then it may well be the chains.

I believe Thomson has just changed the chains, though he does have high miles

[KayGee]

Check the airbox spring clips have all been clipped in place. They are a git to do, I have a hooky tool I use but something like a long allen key would do also.

[bigchris]

my s4 has had both manifolds changed to cure a rattle, apparantly a common fault as something comes loose in manifold

[Mc-BigE]

my s4 has had both manifolds changed to cure a rattle, apparantly a common fault as something comes loose in manifold

How much did that cost?? Must have hurt. Does it require engine removal?

Did you have the replace the down pipes as well as the exhaust manifold?

[okkim]

I have the same kind of rattle, and it comes from the exhaust manifold. It is a typical fault, the inside of the manifold cracks, and gets loose. The engine must be removed for those replace. I think that the manifold costs about 600€ here in Finland. I made those by myself: http://www.valitalo.org/manifold.htm There is also a picture from a broken manifold. Pieces of it goes straight through from turbine blades and breakes it.

[Mc-BigE]

Got my car back from Tom Cockings in Yeovil last weekend and drove it back to Southern Ireland on Monday , nice drive!
Tom did a superb job at sorting out my rattle ,he sourced the rattle to two rattling exhaust manifolds that some stupid engineer at Audi dreamt up and hopefully was fired shortly after they started failing!

Tom removed the engine and fitted two new manifolds from Vag-parts in record time and fitted two new TT DV's as my old ones were knackered!
The car drives smoother and quieter , gives me more confidence to push the car more!
Nice one Tom!! the man knows his stuff!

Because I bought the car privately and its 6 years old, my chances of getting audi to foot the bill are unrealistic, however I’m going to write to Audi UK and complain about poor design of the early manifolds on this car,
its not what you’d expect from a car company like Audi.

And now my MAF needs replacing , my local Audi dealer does an exchange one for reasonable money but are they any good? any views on replacement MAF's
any good ones on the market for my stock engine

I also noticed that when I looked at the plug from the MAF there is only 4 female pins and 5 holes , last hole is empty , however there are 5 male pin in the side of the MAF? is this right?

Thanks to everyone for their very helpful advice

Regards
Eric

[SimonS4MTM]

Yes, 4 pins is correct, discussed in the RS4 forum only yesterday.

The exchange MAF's are okay, a new sensor in an exchange unit.

[CliveH]

Glad you got sorted - but if you ever need an S4 specialist in South Wales, Philip Walker (on this forum) is your man - very helpful and knows his stuff.

No, I'm not on commission! just a recommendation from a satisfied customer

[audiboy]

Like Simon said, its brand new sensor in a brand new housing.