Help! S8 Scary Engine Noise...Worried
 

Hi all

My 2002 S8 has developed a worrying engine noise.....any idea what it is?

Not even sure if its safe to drive to the indi!

Sounds like top left of engine as you look as you stand in front of car

Link below can be cut and pasted into browser to listen

Thanks
Mark


http://youtu.be/rhE6tbx_cw8

I presume that the revs were steady at tickover throughout that clip? Does it change with revs?
If I remember you dont have VCDS?

Hard to say from video but it could be secondary air injection pump if the noise come from air filter box area in which case you could just temporarily disconnect it. If you have VCDS you might be able to test it using output tests or as Audi call them final control diagnosis.

Revs are constant - no change, it still revs drives etc., no misfire
I don't have VCDS - but may take car off the road and order it!

I did have a fault code for that a while back (from a hand held diagnostic) - the noise sounds higher up than the air filter box

Noise seems to resonate more when I take the oil filler cap off....

It does sound like some sort of electric fan is constantly on as Ainarssems says.
I assume the electric radiator fan is not turning when you hear the noise?

No fan is not on. I am nor driving it today and am ordering VCDS for myself to see if that points me in the right direction!

Could it possibly be the engine block breather valve giving up the ghost?

Where do I find this and how do I test it?

I think you're onto something there! perhaps the rubber diaphragm has failed and is vibrating as it lets air out?

Its the black plastic UFO type object at the back of the engine.

Here it is in a picture I borrowed from another forum member's post as it shows the engine bay without covers.

It is easy to remove by jubilee clip or the Audi type clip, but I'm not sure if its safe to run the engine without it or with the rubber hose plugged to test if the noise stops?
Probably ok for a minute or two, as its just a sprung rubber diaphragm to let some crankcase pressure out when it builds up enough to be able to open the diaphragm.

This is how it looks inside:

http://forums.quattroworld.com/a8/threads/8649.phtml

http://forum.a8parts.co.uk/attachmen...1&d=1420113692

Having had mine off it's held by Clic-R collars/clamps which are best removed/replaced with specialist pliers.

Thank you, I have the plastic covers off the engine, so have seen this
Will run car to see if this is the culprit
Appreciate the ideas

Any idea how to disconnect? Plug seems to be behind air box and I can't get my hand in there! Does air box have to come out first?

Anybody know?
Thanks

Are you sure you cant reach in behind the airbox and unplug it? I removed my airbox before, I am sure I unplugged it first before taking the airbox out. I just went out to the car, my SAI has been removed but I can easily reach to where the plug used to be.

The air tube that goes from the pump through the air box and out the other side of it is in the way

If the air tube detaches from the back of the air box near the plug then I could reach, but sure how that detaches from the air box, and I dont want to break it!

If you know how tube comes off, then that should give me room to get to the plug

Ah, yes, sorry I forgot about the rubber tube. It is a press fit into the airbox and would have to be taken off the SAI motor unit from inside the airbox. Its really difficult to squeeze through that hole so not worth it if there is a easier way.
I wonder if there is a fuse in the fuse box that only relates to the SAI motor? That would be a much easier way to temporarily disconnect it.

There should be a fuse somewhere, not sure where. There is relay for it in electronics box in plenum chamber, fuse might be next to relay.

Guess I need a fuse diagram now

I think I found it, should be fuse S130, a 50A fuse. I cant work out where its supposed to be in the drivers footwell on the side, or in one of the other fuse boxes. Maybe I'm being thick I cant find a fuse diagram in ElsaWin, surely there should be one?
Relay should be no. 4 in the passaenger footwell?

http://forum.a8parts.co.uk/attachmen...1&d=1420394804

Will try and find fuse and/or relay

can i pull the relay and not the fuse?

Pulling the relay will do no harm, might throw an error but you won't damage anything.

Eureka! This is the problem, found this was the noise this afternoon
Can anybody help with a part number so I can order a new one
I assume its easy enough to change over
Thanks

The part number is 077103245B. As for fitting, it is held in place by two clips. I had mine replaced a little while back and just used bog standard Jubilee clips instead of the OEM type used by Audi.

Great - thank you

Same component failed on our A6 Avant 3.0 petrol - sounded horrific but noise went away off idle. On stripping it the valve was full of crud, so be prepared to spend some time removing pipes in the vicinity and checking they're not blocked and/or squidgy from oil.

Not sure if it's the same for the '8 as was the case for the A6 but there were 2 part numbers, one being for a kit which included more bits and wasn't much different on price but included a couple of pipes - worth querying when you order +++

I will check when I order
Thanks for the advice

It's worth just taking it off (dead easy with the right clic-r tool) and taking it apart (very simple) and checking/cleaning it.

Mine had a tiny tear in the very edge of the diaphragm which I reckoned wasn't a problem (probably clamped between the two halves of the body) but I bought a new one eventually just in case.

Once it's cleaned it's very easy to test it works by sucking and blowing into the appropriate orifice!

Kept my old one anyway as "backup". Part number on the casing is 077 103 245 B.

I bought myself a pair of the right pliers to remove the clips - so shouldn't be an issue to get it off
Will take apart and have a look
I have ordered a part - but if the other one seems serviceable, will keep it as spare too
Thanks

Just a minor point on removal/replacement.
The tool you use is turned 180 degrees between removal and installation mode, hopefully not a huge change in angle but how much will depend on the design of the tool you have. I had a bit of a struggle to get it onto one of the clips for removal.

So, when you put it back together just decide carefully where to place the clip so that it's easy to get at for both jobs.
IIRC I removed the side pipe first then had to bend and twist a fair bit to get at the one underneath.

I've looked where they are. Tool was just from ebay so hope its up to the job
The one underneath did look like a bit of a faff!

Mine too, about £7.50 I think. Not great, but did the job.
Once the side pipe is disconnected you can be pretty brutal bending and twisting to get at the bottom one.

Maybe the same one?

http://www.ebay.co.uk/itm/1213719467...%3AMEBIDX%3AIT

Different seller, but exact same tool. :cool:

Excellent! That's a easy fix.
If you end up needing a new one I think it is part no. 077103245B
for a 2001 S8. I think I paid the dealer around £100.

Its probably making a noise because the orange rubber diaphragm has split or fallen apart, but worth checking anyway just in case it just needs some cleaning.

I think Mark has already ordered one, but I got one from the USA for the princely sum of £27 including shipping!

I have ordered one - but because I was in a bit of a hurry I went with the dealer - cost £67 but it will be here Thursday,so I an fit at the week-end

Ah, should have read more carefully.
Was the USA one an Audi original part, or if not, is it working fine?
I'll be needing another one for the current S8, no harm in saving some money :)

Yes, found it on eBay. Works fine.
Plenty available in US (and some in Germany), you just need to look carefully at the shipping and (for US) customs charges.

Parts not arrived yet - will it do damage driving it??
Its not noisy all the time............
Thanks