kkaugars

Hi, new to this forum but hope to get some advice / help.

We have a 2004 A6 3.0. Last week, the low oil indicator came on, and since this is a somewhat regular occurrence, my spouse added a quart - pulled the dipstick, nearly dry, added another and repeated three more times. Told me when we both got home (she drove around 60 miles total to work and back), I pulled the dipstick and it was way overfilled.

I did a full oil and filter change, since the car was nearly due in any case and I figured I would get the right amount of oil in the car using this mechanism. In the past, I have under-filled to 5.5 quarts and then carefully topped it off. Followed the same procedure, but after the 5.5 the dipstick showed an overfill.

Thinking that the oil filter had not filled yet, I started it and immediately got intense oily smoke pouring out of the tailpipe. Thicker than any fog I have ever seen, almost like the car was burning pure oil. Immediately stopped the car, let it sit for a day in frustration. I opened up the oil drain plug this morning and perhaps a 1/2 quart at most dribbled out.

I am at a loss - it appears something is plugged, but where to start hunting, or if it is even worth it are open questions for me. If there is a common issue here that I may be able to resolve, no problem. If I am faced with another multi-thousand bill from the dealer, time to start looking for a new vehicle.

Any help or advice gratefully accepted...

uberwgn

FWIW, oil is always checked after a 5 minute hot shutdown.

It's hard to imagine how 5 quarts of oil disappeared from the crankcase and was consumed and expelled by the engine...

Do you know how many miles are on the car? What other issues has this car suffered?

The oil level sensors do fail. People end up dumping in a bunch of oil when the level isn't even low. I assume a car of your vintage has this sensor and a regular dipstick.

kkaugars

Same here - I am mystified how pouring 5+ qt into the top never made it to the oil pan. Seems to me (but I may be wrong) that the car was not running long enough (maybe 30sec tops) to burn it all off.

The car has approx 186,000 miles. Aside from issues with rusting exhaust pipes, failed heat shields, replaced water pump, and similar things one would expect from a 10 year old car, no major trouble until this event.

I have been poking around trying to find a nice engine diagram that would help me explain a saturated dipstick and an empty oil pan - I know next to nothing about this engine, but that piece of it makes absolutely no sense to me whatsoever.

SloopJohnB@mac.com

One guy on the forum has had a plugged oil passage in the head IIRC that necessitated heads if not engine replacement…
It was/is a 4.2 V8 engine, but…
https://www.audiworld.com/forums/sho...php?p=24569401

Just Me

Let's start with the basics:

1. car must be truly level
2. oil is measured hot. When cold the level shows lower than it will be fully hot
3. oil flows down and into the sump slowly. this is an issue at the track when it takes 15 minutes level for me to get a good reading (not the audi, but motors are motors)


I did have a truly mysterious subaru lately that was IMPOSSIBLE to read, and seemed to fill and settle as if it was molasses.

Grant

kkaugars

Not so much a mystery of how to measure oil level, but more of a mystery of where the oil might be right now.

5.5 qts entered the valve cover and went missing. Things established so far are that the oil is not on the ground or in the oil pan. It has not made it to the pan in a day. Car produces incredible amounts of blue gray oil smoke when started, so some (most?) is certainly in the cylinders. I suspect SloopJohnB's hypothesis about plugged oil passages might be correct.

I am thinking I will drop the pan tonight or tomorrow and see if I can determine where the blockage might be, but fear I will be wasting time.

SloopJohnB@mac.com

Oil is not in cylinders…oil is incompressible so if it were IN the cylinders the engine would be hydrolocked if not damaged. Engine runs, ergo not in cylinders.
That doesn't mean oil isn't getting into cylinders when engine is running…chiefly through the valve seals because chances are you have 5.5L less whatever has been sucked into the PCV system in the right side (oil fill port) cylinder head. If you remove that valve cover you may see a lot of oil and be able to run a rifle brush or coat hanger wire down the drain hole(s) from the head into the crankcase. If you don't see a lot of oil, the oil is in the PCV system/hoses. Time to start removing hoses…find the lowest one and open it at a connector or like most people do just cut the #$%@#$% thing off and replace it with new ones…spendy, but chances are your PCV hoses are toast or plugged anyway.

Back to the future….if you pour oil into the head (oil filler port) and it doesn't make it to the crankcase the drain to the crankcase is plugged…it needs to be unplugged. Whether you have oil in the head or it all got into the PCV you still need to pull the cam cover(s).

Redd

Unless Audi has gone and "improved" standard engineering again, there should be multiple oil passages that ensure the oil drains down from the head. But if somehow they were all blocked and 5.5 quarts (not liters?) of oil were in the head, it might be running past the valves and that could explain a smoky startup.

Never have heard of an engine that could fail to drain that way, but there are (or were) cleaners to clean out engines. Shade-tree mechanics would just fill it with kerosene and run the engine for a few minutes, then drain the kero, replace with oil, run again and replace again. But if the oil passages are blocked, you really want to tear into things and try a thorough cleaning. Before you have a total lube failure and an engine meltdown, which would seem to be in the immediate future if all the oil drains really are that clogged.

SloopJohnB@mac.com

Pull the cam cover on the oil fill bank and look.

ajg617

Couple of things to check.

Oil doesn't disappear and from the way you describe, the heavy blue smoke occurring after an oil change wasn't enough to burn 5 quarts in a couple of seconds of running. Personally, I think you may have more than one problem at play here.

1) You might have sludge in the bottom of the oil pan as well as plugging the head drains, especially the lower drain holes which would plug first on a V engine and as a result keep much more oil around the cams rather than draining back down. If you put 5.5 qts in after a full drain, run the engine to fill the filter, and it reads overfull, something is in the pan that is displacing where the oil should be. Your use of the term dribbling out of the drain makes me a little suspicious. But that doesn't make sense with only a half quart coming out the next day unless something was preventing it from draining. The oil level sensor is screwed into the bottom of the oil pan and it is temperature sensitive. If there is a lot of sludge around it, it may not read correctly and possibly indicate a low oil condition when there is none. You might want to pull the sensor out (replace the screws and seal at the end). It's a larger hole and you should be able to see or feel what is really in the bottom of the pan.

Have some one put a couple of quarts in the fill while you watch what comes out the drain plug. If it is a dribble or very much delayed in coming out the drain plug, I'd pull the valve covers and inspect for blockages up top.

2) Check the crankcase vent tubes to see how plugged they are when you do that. You might replaced the PCV/PRV as a blocked PCV or PRV will cause excessive oil consumption due to higher crankcase pressure forcing more oil through valve seals and rings, especially on a high mileage engine. I just changed mine at 205K and the difference in weight between the old and new were amazing. I haven't pulled the old one apart, but now I'll be interested in seeing if my oil consumption goes down (1 qt every 1500 miles).

Is there any evidence of oil leaks anywhere?

Good luck.