Oil consumption after a long drive.

B6/7 S4/RS4
#1

I think we have all seen this from time to time. You go for a nice long drive and then BAM a low Oil light and you just found out that your car ate a good amount of oil.

Its always hard to pin point what is going on with every car in every situation. While there can always be 50 other things that can be considered something to look into. The main starters would be what Im listing below.

First thing is to consider the oil your using. The thinner your oil is the more it can breakdown. The more it will breakdown the more likely you are to have the oil actually pass the rings over long constant RPMs. This is common on just about any car. Its going to be a little more so on the Aluminum blocks. The blocks are prone to warp this causes a more oval take to the boar, this leaves the thin oil a chance to get into the combustion side of the cylinder and then eaten on the power stroke.

Next is the PCV system. Lots of S4s have a PCV system that likes to eat oil one week and then seal up and not eat oil for weeks at at time. I know there is a member here who actually put on a brand new PCV system only to find the NEW OEM PCV system to actually be faulty and by extension contributed to eating oil.

Last is check those crank seals along with the ever scary Valve cover gaskets

http://audirevolution.net/addons/albums/images/231902678.jpg

This next picture shows a cylinder that would still do well on a compression test but is typical to eating bits of oil. The lines in the wall are not good. There more prone to only let the thin thin broken down oil by. This motor could still be used for thousands and thousands of miles as long as the walls didn’t get worse. Still this is an example of how there is passages for oil to sneak by

http://audirevolution.net/addons/albums/images/911798652.jpg

1 Like
#2

count, great informative post once again. do you think we could benefit from a heavier weight oil, say a 10w40? i know the tolerences of newer cars are much tighter thus no more need for 150w50 or 20w50 like i was told to use on my old 5 cylinders, but with the problems many of us are experiencing with oil consumption for various reasons whether being something small like valve cover gaskets, to pcv to crank seals to scored walls, would a thicker oil help out at all?

#3

Great info Count. I should be able to contribute to this thread in the near future hopefully.

Another cause could be leaky valve stem guides correct? I know from experience that once there is too much play in those guides or something preventing a perfect seal when closing there is room for oil to sneak by. While the car is running or sitting over night. I believe the overnight slow leak will lead to that puff of blue smoke upon a cold start up.

Either way, if my motor gets pulled and torn down again…which I think it will be…I will be bring my D90 this time and take a bazillion pictures this time around so everyone can view the inside of an RS4 block and the differences from the S4 blocks. I will aslo take pictures of the culprit of my oil consumption if possible so we all know what this mystery issue finally is.

Some different items found inside the RS4 block; the funky shape of the top of the piston, the different head design, intake manifold design etc. All these little differences are interesting to me.

#4

I.E. the awesome compression & High Rev the RS4 engine/internals! Those pics are great though, so keep em coming and get as many as you can if ya get the chance.

Thanks for this post and info Count, good info and I’ll be interested to see you expand on it some more.

#5

Great post - as 91 says as our cars get on in miles and what point is the recommended oil from Audi no longer good enough.

#6

Wont lie, I’m a former B5 S4 guy, and this Oil consumption with the 4.2 is one of the main reasons why I haven’t pulled the trigger yet on a B6/B7 S4… Still kinda iffy even with all the threads Ive read regarding this issue…

#7

Great post CountVohn, it’s like Audi designed these things to consume oil in some way.

#8

Does anyone have a 4.2 that realistically doesnt burn/consumes much oil, or is it something that the 4.2 guys just have to live with?

#9

Think about it…think about it…see it yet?

http://i183.photobucket.com/albums/x59/joec1992/count.png

#10

Yea i realized that 2 secs after I posted it, lol… I fixed it, hoping before you replied…lol But too late.

#11

No problem, I knew you just missed it. To answer your other post, I changed my front crank seal, and my valve cover gaskets, as well as cleaned my PCV valve and mine only goes through about 1 quart every 3000 miles which is probably better than most. I consume some every time I start my car, because my valve seals leak some oil when the car is sitting and cold. I get a nice blue plume when I first start the car.

Vid of smoke awesomeness:
http://www.youtube.com/watch?v=PZxT4kPn_kY

#12

Cool ;D … With that aside, do you get that heavy oil/burning smell in the cabin tho?

#13

Well I’m catless…so there’s always a smell of something burning. Definitely not just the smell of oil burning. I get more smell when I’m really pushing the car, but that’s expected

#14

Ah o.k… Yeah like I said really looking to get into a B6, but trying to sort out the in’s and outs of the 4.2.

#15

The best thing you can do is find one with a good service history and/or have a proper compression AND leak down test done before you buy it. Most S4’s are very well taken care off. the difference between a good one and a bad one all boils down to how it was maintained. Audi recommended 10k oil changes are practically a death sentence, and one that was beaten on when it was cold will have scored cylinders which almost always shows itself in a compression test.

I bought mine with 83k on it from a guy who changed the oil himself every 4000 miles with M1 0w-40, and mine is one of the better as far as consumption goes for a car with 98k on it so that proves that it’s all in the maintinence. He was a car guy too, the S4 was his daily driver. He had a Shelby Cobra Replica in his garage, and was replacing the Audi for fuel economy reasons. Point is, the type of owner tells the story. The guy even texted me a few weeks after I got it reminding me to change the oil after my 1000 mile trip home!

#16

Like most, I always have at the back of my mind “when’s my timing system going to go boom?” or “how badly scored are my cylinders?” So I have mostly been reluctant to post my oil experience in fear of jinxing it!

I had my valve cover gaskets done about a year ago (about 8000km ago) because, like the count, it was noted my engine is caked in oil while a power steering line was being fixed. I had an oil change at that time. I went about 4000km before my next oil change and I did not need to top up the oil once. I did another 3000km and got another oil change. Again no topping up in between. My intervals are probably excessively short but I do a lot of short trips and the engine spends much of its time warming up.

Even before I had the VC gaskets done, I did not notice any excessive oil consumption. Maybe 1 quart over 5000km. Certainly no more than my old 2.0 TDI.

#17

I have a 2004 B6 S4 Avant with 55,000 miles that doesn’t use a drop of oil. ;D

#18

^ consider yourself lucky! mine didnt burn a drop with the first motor either. damn timing chain guides took its life

this new motor is mint too. everything is new and it works flawlessly. nothing better than not having to hear your chains on startup or smell oil burning!

#19

91, depict your chain failure…mine are rattling bad

#20

he started getting codes

then he started going back through time and used his chains as an excuse for why my B7 S4 whipped his ass in the 1320