V8 oil level/usage confusion...

[re2500]

Ok, this is a bit of a long winded story so im going to try and summarise first.

0 miles - oil max
90 miles - oil min warning on dash
add 0.3l oil
171 miles - oil min warning on dash
Check oil after 5 mins, appears to be max on dipstick
Oil warning dissapears??
470 miles - oil min on dipstick (no warning)
add 1 litre of oil - oil max on dipstick
820 miles no warning lights for 300+ miles journey.
Park Car
Check oil in morning, oil 1cm above max??

Car does not appear to burn or leak much oil.

In exact terms, i never notice any oily residue on the back of the car although the exhaust tips do slowly blacken over time, and although the undertray is not oil free, it does not leave a patch at all on my driveway.


Full story of circumstances if you're interested.......

I drove up to the Scottish Borders from South Wales this weekend, and i cant work out whats going on with the Oil level.

I set off with the oil level reading max on the dipstick and a 1 litre top-up in the boot (how very organised and responsible of me )

At Birmingham approx 1.5 hours in i got the Yellow "Oil level Min" warning on the dash, which i thought was weird, being as it was on the max when i left.
I had to stop for fuel anyway, but of course the car was warm and i couldnt get an accurate reading on the dipstick, so i put about 0.3 litre in to make sure i wasn't too low. Continued journey...

Another hour or so in and the same warning light appeared again, so i thought little of it and when we stopped at a services (woodall) near Sheffield we had a toilet brake and picked up a coffee, when i returned i checked the oil and it appeared to be on the max so i added no oil and continued.

The warning light disappeared and did not reappear for the whole journey up north.

I did about 120miles whilst up north without a problem, i checked the oil as a matter of course before leaving (cold engine, left overnight) and it was on the min marker. I added the remaining 0.7litres of oil i had with me which took it up to about 3/5 ont he dipstick, obviously assuming the current rate of usage i decided i would be below the min before i got home again so i bought another top up bottle (without starting the car) and topped it off to the max marker.

I drove about 350 miles home again without any warnings on the dash and parked up.

This morning i checked the oil to see how much i had used (expecting it to be on the min) yet the dipstick is showing about 1cm ABOVE the max marker?

I can only assume oil is getting stuck somewhere and not returning to the sump somehow?

Oil and filter were changed 3k miles ago, and oil is still golden amber in colour.

Any ideas?

I know this car isn't an S2 but you guys on here, are more knowledgeable and mechanically minded than i have found on any other forum, so i thought i'd ask here first, im more likely to get good suggestions here.... if anyone has any suggestions of any other knowledgeable forums that may know about these engines, then let me know.

[S2central.net]

What generation V8 donkey are we talking about here - like on B6 or something else ?

My own B6 V8 is a bit oil hungry (especially on high speed motorway cruise) - tis a common affliction on that engine, but yours sounds more like a potential issue with the oil level sensor not behaving consistently... then again it doesn't quite explain everything !

[re2500]

B6 S4 BBK engine, so yeah the same as yours..

I was sure it was the level sensor also, until i checked it this morning and there's way too much oil in there its like its generated an extra litre over 350 miles

[re2500]

I'm thinking that something is occasionally holding the oil in one of the cylinder heads, a blocked oilway (engine seems clean judging by oil colour), dicky valve somewhere...

[S2central.net]

Yeah mine is inconsistent too... I once consumed a liter of oil on a ~80mph run over about 40 miles - that was quite scary, but it never misbehaved as much as that again.

I suspect its some kind of blockage or inefficiency in the breather system - there are quite a lot of confusing threads on other Audi forums which never quite fill me with confidence. Sometimes I smell oil where it sweats out of the top gaskets and onto the EM, but I am not losing anything like a significant amount there.

Its like the PCV valve sometimes sticks open forcing the engine to consume lots of vapour (that would otherwise condense back into the sump)...

I did buy new gaskets, new PCV and new head covers (plastic ones superior to crap quality metal ones with internal paint that flakes into oil) at great expense - but I've just not been in the mood to attack it yet... I should really check compression ratios across all 8 cyls as well just in case I have a weak ring (matron).

[S2central.net]

PS - I moved this thread to the correct sub-forum.

[re2500]

Yeah mine is inconsistent too... I once consumed a liter of oil on a ~80mph run over about 40 miles - that was quite scary, but it never misbehaved as much as that again.

I suspect its some kind of blockage or inefficiency in the breather system - there are quite a lot of confusing threads on other Audi forums which never quite fill me with confidence. Sometimes I smell oil where it sweats out of the top gaskets and onto the EM, but I am not losing anything like a significant amount there.

Its like the PCV valve sometimes sticks open forcing the engine to consume lots of vapour (that would otherwise condense back into the sump)...

I did buy new gaskets, new PCV and new head covers (plastic ones superior to crap quality metal ones with internal paint that flakes into oil) at great expense - but I've just not been in the mood to attack it yet... I should really check compression ratios across all 8 cyls as well just in case I have a weak ring (matron).

Yeah ive been searching but only found discussions with no real sensible answers. I sometimes get the oil on manifold smell, but not always...???

How much was that parts list above, if you dont mind me asking? as i may end up taking the valve covers off, to investigate, in which case all those parts could be replaced at the same time....

Thanks for moving the thread, i'll try and post in here from now on with anything b6 related.
Ive just noticed though that threads in here dont seem to pop up on the home page under "latest threads"?

[S2central.net]

You will depress me if I have to look at that receipt from TPS again but I don't think there was much change from £400. Access to the bolts is a ****** too - needs very compact 1/4 inch drive and joints.

Most annoyingly the right side cable cover is NLA already - some muppet "technician" at Audi must have damaged both of mine when Audi did the coil pack recall before my time. I am being OCD of course but it just irks me that one side is available and other isn't apparently.

Need to tweak forum settings so updates here show with the rest of threads.

[re2500]

You will depress me if I have to look at that receipt from TPS again but I don't think there was much change from £400. Access to the bolts is a ****** too - needs very compact 1/4 inch drive and joints.

Most annoyingly the right side cable cover is NLA already - some muppet "technician" at Audi must have damaged both of mine when Audi did the coil pack recall before my time. I am being OCD of course but it just irks me that one side is available and other isn't apparently.

Damn! One of the reasons i got a newer "S" car was to avoid the NLA stuff for another few years. I need to check if mine has had the coil pack recall yet, and get it done if not. I'll start some serious s**t at the dealers if they break that and its NLA....

I dont think working on any part of this engine is easy, much patience required!!

[S2central.net]

Agreed 100% - I was a bit gobsmacked too... there must be a suitable alternative but I haven't found it yet !

[re2500]

I have a theory that all my oil level inaccuracy woes are due to the oil check valves located in the valley pan. (This holds oil when the engine is stopped to keep the hydraulic lifters and the timing chain tensioners primed with oil for the next start up.)
They can stick open and cause the oil to drain into the sump. It would cause the oil level to be all over the place. it would also cause some of the occasional 0.5s chain rattle on cold or warm start up.
Ive just ordered all the parts to do the check valves and gaskets, cam cover gaskets, PCV valve and oil level sensor. I'm going to do the lot along with an oil change. I'll try and do a nice write up with it and post it up. I'm convinced it could be the key to prolonging chain life...

[Error404]

I keep putting this check valve job off - you'll have to let me know how much the damage is on those parts mate. Check your valve covers when they are off too, mine are warped and they do leak a bit. Worth skimming them if you have access to a mill, I would if I could.
Oil level sensor I already replaced a couple years ago and it is playing up again after just 12k miles

OH! send me the p/n for those lower spring perches we were talking about

[re2500]

Yeah, i'll check the flatness of those covers. Good idea!
The check valves and valley gaskets came to £90. I'll put lots of detail in a write up.

[Monkeymagic]

Oil level sensor should throw a fault code
Fairly common failures on v6 and v8. Make sure you buy a hella one the cheap ones are crap. Also I know some can play up to due to faults with the bonnet release catch. The catch tells the ecu the bonnet has been opened and assumes level has been checked.
My b5 rs4 is an **** to get the same reading on dipstick from one day to next. I always check on same surface now and it's constant. Could the shallow sump be the cause?

[re2500]

Im sure my inconsistent level readings on the dipstick are due to whether the valley pan holds or drains (sticky valve) for no other reason could i be gaining oil from one check to the other. It explains a number if intermittent behaviours. Car is always level when i check the oil. You are right, the shallow sump can effect readings.
I bought a meyle oil level sensor that i will fit also. Good to note that upon opening the meyle box i have found it to be a hella unit anyway...

Interesting to know about the bonnet sensor, that would explain why sometimes checking the oil makes the warning go away....