Drinking oil but no leak

[rich_5259]

Just got my car back from the garage to be told they can't find any leak, there is no pool of oil in the under-tray nor any streaking on the underside of the car (it was on the ramps and i had a good look with the service manager) and it's not dropping onto the exhaust and being burnt off, nor is it being burnt in the engine

It was using a litre in about 500 miles before, due to leaky rocker cover gaskets and oil pressure switch - I had these fixed and when i was on holiday last week it used 4 litres in 1400 miles. The low oil level sensor is working correctly and the oil is definitely going down on the dipstick.

does anyone more knowledgeable have any suggestions on what the problem is?

[xyber]

What oil are you using?

[rich_5259]

I'm on Fuch's Titan Race Pro S 5W-40 which has cured the cam chain tensioner rattle it used to have at start-up

[gottanS]

Did it have this level of oil consumption before changing to the Fuch's oil?

You say it is not burning the oil, have you checked the exhaust tips to see if they are oily or have heavy soot contamination?

Only other suggestion would be a compression test on the engine.

[rich_5259]

It was using about 50% of this before the gaskets were changed, both on generic 5w-30 and Fuch's. The exhausts are not showing signs of oil but I'll have a look in daylight to check if they are particularly sooty

it's sounding like a compression test is needed to make sure I don't have a valve that isn't closing fully

[xyber]

Find a garage with a borescope and check out the cylinder walls for any scoring.
You may find it settles again on it's own

[linkman72]

I know V8's use a bit of oil but must say if These Audi's are revved hard they do like a drink, i just used a litre after about 500 miles of hard driving ( new car still so still playing ) Audi told me that is not uncommon and sold me a load of diamonds/gold/heroine -- ahem sorry Castrol edge proffessional and sent me on my way.

[sulli]

Seems to be a trait of the S4 - rev it harder and it'll use more. My E39 5.0 V8 M5 was just the same - no big deal. Just enjoy it, top it up and relish the fact that you are effectively changing the oil every few thousand miles without getting under and removing the undertray and sump plug

[BlingBling]

There are many things that can cause high oil consumption from poor/old oil to scored bores or leaking valve stem oil seals. The best way to put your mind to rest would be to perform a compression test. This will dismiss scored bores.

[Madmonkee]

Turns out my driverside rocker cover is leaking... as I had the airbox out (RS4 B7) thought I'd try tightening the bolts as an interim solution... bottom three closet to the gasket weren't even finger tight!??

[rich_5259]

Holy thread resurrection Batman, this is a blast from the past - I'm on my 2nd car since i got rid of the S4.

I had it checked out, it passed the compression test but there was evidence of soot in the LH bank of cylinders which was pointing towards the scavenge rings being worn or damaged. The dealer offered to strip it down and check or replace bit that is 20 hours work at £100/hr

I traded it in at a different dealer for a nice shiny S5 coupe which has since gone back to be upgraded to an A6 Avant oil burner due to having to transport a dog and my octogenarian parents about the place, but as it has the bi-turbo engine it's just as quick as the coupe was even it it's not as stylish. Oh, and it does 36 to the gallon rather than 24