Oil Consumption Question

B6/7 S4/RS4
#1

So I picked up a used B7 about 18 months ago with around 85K on it, though talking to Audi I learned that it got a new long block at 65K or so for high oil consumption, so I was looking at a car with only 20K on the motor. Fast forward to about 4 months ago (100K or so) and all of a sudden it has started burning about a quart per 800-1000 miles. I’ve been running Mobil 1 0W-40 in it since I got it.

While I figured it was a major shot in the dark, I contacted AoA to see if they would do anything about the new engine burning so much oil with only about 40K on it. They had me take it to the local dealer for diagnosis and they found that 3 of 4 cylinders on bank 2 have low compression, though only by a little below the wear limit. They said the wear limit is 9 bar and they are all around 8.5-8.7 bar. The cylinders on the other bank were all somewhere in the 9’s as well. They scoped it too and said there wasn’t any visible scoring or scratches on the cylinder walls. As I pretty much expected AoA said they wouldn’t do anything and then told me it would be $25K for a new long block. I can’t imagine why I’d spend that kind of money on a new engine for the car when the first two haven’t gotten to 70K without giving up. I’d rather invest that $$$ in a whole new car.

In the meantime, does anyone have any recommendations on oil to use to possibly stem the issue for now? Will going to a 5W-40 help at all? Do the expensive Lubro-Moly and others help consumption? I’d hate to fill with that and have to keep replacing quarts as expensive as it goes for.

#2

Welcome to Audirevolution. The good news is you’re on the right site for information and technical support.

Most of this data you can find in searching on the site. Here is what I gathered. I’m sure others will chime in as well.

If you dodged the scored cylinder walls and your compression test is ok then you’d want to check the pcv system. The pcv systems seem to fail and cause great amounts of oil consumption. From there check your seals on the valve covers front and back motor. These can also leak very large amounts of oil. If you don’t have your precats removed do so ASAP. That’ll reduce motor heat and improve motor health

#3

Welcome!

I am assuming your screen name have a B7 S4, not an RS4, although is not explicitly stated in your post.

#4

Welcome to AudiRevolution. You have come to the right site for questions about your car.

I have some questions for you just so we can get more information to better help you.

  1. How many miles do you have now? On both the car and the current engine?

  2. Do you have the paperwork from the previous owner about when the previous engine was replaced? Just to see what was exactly replaced.

  3. Have you done anything different in the past four months? Like switching jobs that caused more highway miles, more city miles, or more time spent sitting in traffic?

  4. Do you have any idea how many miles the oil had when you got the compression test done?

  5. Do you know if the shop had the engine hot, warm, or cold when they did the compression test?
    Don’t worry if you don’t know about questions 4 and 5. I just like to ask.

I really do NOT think that you need a new engine. You want to start with the easy stuff first.

  1. Do you notice any oil spots on the ground where you park the car?
  2. Do you have a belly pan or cover on the bottom of the engine compartment?
  3. Do you smell oil burning when you are driving?
  4. Are your exhaust tips black?
  5. Do you see any smoke while driving? It would probably be blue.

In the morning before you drive to work try running the your fingers along the side of the valve covers. You are looking to see if there is oily residue. Do not do that if your engine is warm or hot because it hurts.

Next I would check the bottom of the engine for leaks. You want to look up front under the front crank pulley, around the oil pan, and on the bottom front of the transmission. Then you want to check the PCV valve like what My S5(afe) Hyden recommended. It can be taken apart to see if it is covered in crusty old oil buildup. The PCV valve is on the back of the intake manifold, between the intake manifold and the cowl wall. They are also cheap if you just want to throw a new PCV valve on there.

If you don’t have any oil leaks and the PCV valve is okay then I would get cylinder leakage tests done. Your cyilnders should be okay with the relatively new engine so the worst case scenario is the valve stem seals have gone bad.

Again as My S5(afe) Hyden already recommended gutting your pre-cats is a fantastic idea to make your engine last longer.

#5

Welcome

BaumerS4 you are in good hands here. JimmyBones is one of the best. Where are you located?

#6

Wow, you guys aren’t kidding that this is the right place. Plenty of responsive and detailed replies. Let’s see if I can answer most or all of the questions.

Yes, sadly it is just an S4, though hopefully someday I can step up to an RS model. I’m located in Chicago suburbs, and the dealer I dealt with was Continental Audi in Naperville, in case anyone is familiar with them.

The car has around 104K miles on it now, so the new engine has roughly 40K miles (I don’t have all data in front of me at work right now). The paperwork that I do have concerning the old engine replacement came from an Audi dealership, and it said that it got a full long block (around $19K at the time) for high oil consumption. I got the car from a dealer, so I never met the previous owner. Very insightful on the new job question, I actually did start a new job right when this started but I just went from a 5 mile or so city/suburbs commute to a 15 mile one. And the first low oil light actually came on my very first day on the job, so I don’t think the commute could have made a difference so quickly.

The oil in the engine when they did the compression test was about 4600 miles, though it’s obviously been refreshed a bit in that time frame with a good 5 or more quarts of new oil added. I don’t know the engine temp when they did it, but I’ll see if I can find out.

The car has the stock engine belly pan, but I haven’t noticed any oil under the car and I’ve had the oil changed once since this issue started and they didn’t see any oil accumulated on the pan. I don’t smell burning oil ever, but my friend mentioned he saw some white/blue smoke from the driver’s side pipes the other day when I accelerated hard, and those pipes are noticeably darker than the two passenger side ones. I never see any myself while driving.

Also, I did install a set of JHM piggie pipes last October, so I’ve got that out of the way. The PCV valve is the one that kind of looks like a flat disc with a outlet pipe on one side, right? Does that have multi-use clamps on it, or the one-time use Audi ones?

#7

If u do change your oil separator/ pcv valve and still a blue smoke coming out of
The pipe u should check for any scored walls or valve seals! Hope not!good luck

#8

The pcv system with that many miles on it can lead to oil consumption on WOT. It is the disk looking thing. It connects the valve to the throttle body. It plugs in the intake track.

Something else to check is your spark plugs. See if they have lots of oil on them.

#9

I like my S4 over a RS4. Soon enough the S4s will start to be beat or equal the RS4s in performance. Just need the built engines to be streamlined and they will open Pandora’s box.

The new job question is something that I had to learn the hard way when I still worked at the dealerships. You probably were low on oil before your first day at the new job and then it just lost enough to turn the light on. With such a short commute before your car probably didn’t get up to operating temperature and now it probably does get up to operating temperature. You would be surprised by how changing your driving habits can make a big difference. For example, my mother’s A4 has leaking valve stem seals and she can drive around town for months without losing much oil. Then go on a trip to Florida and lose three quarts of engine oil.

It is obvious that the problem with your car is on the driver’s side so I would pull the spark plugs to see how they look just as justincredible recommended. Also you may want to have your friend, girlfriend, or somebody else follow you in another car to watch your exhaust while you drive. What you want to do is drive in second or third gear down the highway depending on the local speed limits, then take the engine all the way to redline, and let off the gas completely to let the car roll to about 2-3K rpms again depending on the local speed limits. The other person should be watching for blue smoke while you do this.

Here is a link to the PCV valve on JHM’s website: http://jhmotorsports.com/shop/catalog/crankcase-vent-valve-pcv-oem-for-b6-b7-s4-p-1360.html?cPath=21_56_61_240

#10

Alright, got an appointment setup for an oil change and PCV replacement for next week. I know I really should do it myself, but I live in an apartment and don’t really have a good place to get the car up and remove the infinite number of screws holding the undertray on.

Like I said in my first post, I’ve been running M1 0W-40 in it. Does anyone think it would be worth changing the oil type/weight? Maybe 5W-40 to help out a bit, or one of the fancier oils they sell on ECS/JHM?

#11

M1 0W-40 is good, If you want to try something different, Motul 5W-40 is also a good option. But it sounds like there’s a lot more than just oil selection to cause that type of consumption.

If you do want to start doing oil changes yourself, figure out where the drain plug is on the underbody panel and cut out a ~3-4" circle at the plug that way you can do oil changes without pulling the plastic panels.

#12

Where are you located? There’s lots of experts and able guys on here that have helped me. Motul 5-40 works best for me.

#13

Got the oil changed yesterday and a new PCV installed. I’ll keep an eye on the dipstick now and keep my fingers crossed.

#14

Awesome response and knowledge in this thread. However AOA telling you 25 grand for a long block is crazy. I just got a new long block from Audi and it was 18k with tax, shipping and installation.