mrbusto71

Hey folks, I have an '02 S8 that just had a full synthetic oil change a little under 3k miles ago. I've been on a road trip for 10 days and I've been doing a ton of highway driving (75-80 mph). Today the oil level indicator came on, and I checked and the oil level was low. Put in 2 quarts and the indicator is still on but the dip stick shows the oil is in the acceptable range.

Is this normal? I don't see a leak under the car anywhere, so I'm not sure if this is expected on a long road trip and I should just check oil level every couple of fill ups and add a quart or two as I keep driving.

Any info would be great!

audinutt

I found as the sensors get older if you trigger the low oil, sometimes it takes a while (day or so) for the low oil level to go away.
That being said, you are consuming quite a bit of oil.
I consumed nearly 2 quarts every 3000 miles on my original engine that had 260k on it.
I replaced it with a 100k engine and my consumption is now none.

-Richard

3dmatters2us

My 00 A8 has 134K on it now. I go through 1 quart every 3K miles of driving. I think I have a small leak with one of the valve covers. It drips on the exhaust manifold and turns to smoke, so I don't see drips under the car. Have you every smelled burnt oil after you shut if off? Also, if you are emitting blue smoke out your exhaust, that might indicate rings are leaking oil.

BrianC72gt

It looks like a round black disc about 4" round on top of the back of the engine. Remove it. hot water and dishwashing liquid. Wash it out in the kitchen sink until it runs clear from every opening. Re-install. Forget the aftermarket ones, they suck.

If this doesn't help, you're on your own with the various snake oils that promise to restore seals and/or loosen stuck oil control rings.

silverd2

Probably because the low oil sensor is actually a temperature sensor, instead of a float.

jfrahm

I think the main issue for oil consumption is carbon in the bottom end. Timing pullout from low-quality fuel might be root cause.
To address/prevent my suggestions are:
Try to use top tier gas
Don't skimp on the octane
Use a carbon cleaning fuel additive every few tanks, Techron for example.
In extreme cases [this is not an extreme case] you can pull the plugs and squirt in a decabonizing solution (acetone and ATF for example) and letting it sit a few days. Then suck out the solution, reinstall plugs, experience a huge smoke show.
- The cylinders need to stay plugged or the acetone will evaporate.
- This will cause damage if you try to start the car with the solution in place
- Blowing the solution out the plug holes (cranking) can cause a mess and acetone is bad news.
- Do not run this stuff through the intake as it's rough on seals, etc.
- Try kerosene to clean out the ATF to reduce the smoke on startup
- Change the oil after 50 miles or so
- Smarter to use less drastic measures if you are not trying to save a shortblock with stuck rings

Decarbonizing treatments for DI engines might be an option. They are probably pretty aggressive.

It'd be interesting to try water injection, it's pretty good for removing carbon from piston crowns and once that is done you might get the normal additives to go work on the oil ring carbon over time.

-Joel.

ThaboTheWuff

My 99 D2 has had an oil leak leak since I got it in 2006 - it's got worse over the years probably one or 2 quarts per six months oil change. Always used mobile one and for ****s and giggles decided to switch to Castrol edge in may. I swear the car leaks less oil now and I have oil leaks in multiple places no idea why and it is not winter here in Colorado so still gets pretty hot and car has been up over the passes etc with luggage and my family in it. I used to use Amsoil then said bugger it and switched to the cheaper mobile one but I swear I have less oil leaking now, no idea why Castrol edge would be better it's the same price too. Of course there are numerous theories about what oil does to a gasket that is leaking etc. etc. and adding special additives etc. who knows and perhaps it's all in my head but come winter I'll use Castrol edge again and see if she's leaking less. You could give it a try if this was your first around with a particular brand of synthetic oil.

pocketchange

Most all engines need a little help staying clean.
Marvel Mystery oil is something I use on a regular basis.
A 1/2 qt., in the fuel (all the time) and 1/2 qt., with an oil change.
I'd have a hard time getting a finger-nail of sludge from the entire block. It stays clean.
Bore scope the top of your 4.2L and in most instances you will note that the gas being produced today is for better or worse.. CRAP.
Back in the good ole' days, gas did not crud up the top of an engine the way it does now.
Liqua-Moly (sp) is another product that comes to mind, if you don't mind spending a extra dollar or two. pc