Greg5OH

perhaps my collated thread is not the best idea for answering individual questions..i will leave it just as an update log.

Moving on: 800 miles this weekend, made sure oilw as good before leaving, about 50 miles from how low oil level comes on. shut the car down, check the oil, looks to be right at the min level. put hafla quart in to bring it back up. Checked the mornign after and it was over full actually, Apprantly didnt wait long enough for the oil to drain down when checking at side of the road.
Im doing an oil change today anyway.

However the car was a little low on oil when we bought it.

I am suspecting the PCV/oil separator contraption located on the rear of bank 1 behind the throttle body. I can feel a very good vacuum when I pull the oil cap off, most cars the spec is 1-3", id id have to guess, this is at least 6" of vaccuum.
I don't know what the spec is, anyone know?
I read the diaphragm can go bad or gunk can build up and hang the device up causing excessive vacuum on the crankcase and pulling out through.

Can I disassemble to visually inspect the diaphragm and run some degreaser through it? (on the bench)

mishar

Check oil just after shutting down the engine. After long time it would always be more but it is irrelevant. From the low to the full mark is 1 liter (~1 quart).

You didn't say how much it consumed and how many miles. I believe that PCV story is a wishful thinking, but if it is the cause you will have (already have) a huge carbon buildup.

The.aviator2

To check the oil level on the V10 5.2L, Elsawin states the following:


Start the engine, wait until temp reaches 60C, shut off the engine, wait two minutes and check oil level.


I'm not sure how strictly you should follow this, but I do and I get consistent results. Also, Audi allows for maximum oil consumption of .5 quart every 1000km. I did a 1400km road trip and lost about .5 quart.

Greg5OH

I did 1200 km and used half a quart as well.

I double checked last night, if i pull the oil cap off there is a massive vacuum leak and the car starts bogging down.

Greg5OH

I also, without a doubt expect this car to have car bon buildup, unless it was done before my ownership which i doubt. I have an inspection camera i will stuff down the intake one of these days to investigate.

I read ton the A4 2.0T forums, crankcase vacuum should be 1" (like most normal cars, 1-13")
I havent stuck a vac gauge onto the dipstick to double check but just form pulling the cap off I can tell it is way more than 3". Id say its full manifold vacuum.

I ordered a cheapo PCV off ebay as the vaico unit wont ship from ECS till sept 15, it was $35. Will test it out as it looks very simple and quick to swap.

i suspect it is consuming the oil right at highway speed, where there is a decent amount of vacuum. As there is no blue smoke on start up, nor is there any on hard acceleration.

gravesja@outlook.com

I had the exact same problem on multiple trips with my 4.2 Phaeton. The gasket on my oil fill cap looked a little chewed up, so I replaced the cap and have not had the problem reoccur. I think I was leaking oil out of the cap.

Audios_79

HI there, by any chance do you have the part# for the PCV you ordered from ECS? Thanks.

Greg5OH

No i did not order from ECS, think it was rock auto or ebay, just generic unit.
It was still more/less the same.
However last 2 oil changes I have used valvoline instead of Mobil 1 0w40...appears to be much less, I have done over 2.5k miles since the last change and have not noticed a decrease on the dip stock nor has the level dinged at me. Usually on my 800 mile round trip it may ding at me within 1000 miles, only takes .5-3/4 quart to get back to full (touchy little thing), but still.

Audios_79

Thanks Greg for the reply back, is it just called a PCV hose?, sorry for the newbie question, could you provide a part# or pic where its located in the engine bay whenever you get the time, Thanks .

This is my first Audi ever; I just got few days back, and that too an S8 which I always wanted. I had previously a Jaguar S type R and Mercedes S55 AMG, but this S8 is something special in its own way :O).

So just to confirm, the oil level should be just below the MaX line on dipstick for these V10's or btw the max and min? I'm considering using Mobil 1 extended 15k, fully synthetic 10w30 oil ( Florida weather year round is pretty warm and hot, so I guess a little thicker oil like 10w30 should be ok?).

After that, will do a complete tune up, change out the Plugs, air filter, cabin filter, and fuel filter. At the moment I have 95k miles on her.

Thanks again, Tarek!

Greg5OH

10w30 is technicaly thinner at the hot end of the oil spectrum than a 0w40.
for a hot climate thicker oil is ok, even say a 20w50 (im not recommending that, oil weight is determined by bearing clearances).

say in my diesel truck, I will run 10w30 in the winter, but 15w40 in the summer.
15w40 is molasses when cold. 10w30 is pourable.

the part I changed is technically called a fine oil mist separator (course separation occurs in teh valve cover labyrinth). But most places will just call it the PCV valve.

looks like this:


It is located on the driver (left) side of the engine at the back. To remove it disconnect the PCV hoses (1" diameter corrugated plastic hose) from it, then it is 2 or 3 t25 torx screws holding it. Tight fit but can be changed with jsut hand tools.

My plastic PCV hoses cracked from heat and age, I replaced with oil rated good year hose, didnt want to pay 80$ for a piece of plastic hose.