Castrol 5w40, 2725 mi, 06 S4 4.2L

[gdawga4]

This is my first UOA on the S4. A little history...I bought her with 68k miles in June '10 and is currently at 90,xxx. She consumes oil, unfortunately. The service records never indicated the previous owner complained about oil consumption. Consumption ranges from 200 - 500 mi/qt depending on the oil used. TCW-3 in the gas helps minimally. Oils I've used (in order of use):

M1 5w40 TDT (~500 mi / qt)
Rotella T5 10w30 (~500 mi / qt)
PYB 10w40 (AutoRX) (~500 mi / qt)
Rotella T6 5w40 (~500 mi / qt)
Castrol 5w40 (~400 mi / qt)
M1 10w40 HM (~200-250 mi / qt, the worse out of the bunch)

The BHF 4.2L is known for consuming oil and commonly due to cylinder wall scoring. We took a scope and looked at each cylinder but found no signs of scoring. We did notice a lot of carbon on the tops of the pistons, basically covered. A thought was that the piston rings are coked in carbon. AutoRX did nothing to help the issue, maybe cleaned out the valve train. It was quite clean when I did the valve cover gaskets. A piston soak using Seafoam did not help either (done early on). It cleaned off some of the carbon on the pistons at that time but has since returned.

I did a compression test and it was within spec. I don't have the numbers in front of me to reference. Once some oil was added to each cylinder and re-tested, the numbers did shoot up.

This past weekend, I ran BG 109 in the oil before changing it out. I've read several success stories on here helping to reduce consumption and restore some compression, if gummed up rings were the issue. After putting some miles on, it definitely feels peppier compared to before. I should note that I never felt it was down on power before. She pulled hard before the BG treatment but now feels even better. Maybe it's in my head. I checked the level after 150 mi and it's 1/4 low. Signs of improvement however time will tell. Current fill is GC 0w30. I've basically been buying what's on sale from AZ or AAP.

Sorry for the long read but thought it would be good to provide the history. The report from Blackstone is below. Per their comments, there's nothing that jumps out as the cause for consumption. Thoughts? Comments?

 

[addyguy]

If it's been driven really hard, the rings are worn, pure and simple.

During the summer, I'd try a 50wt., just to see what happens - 15W-50, 5W-50, 20W-50....just to see if viscosity is the only thing that changes it.

 

[dparm]

I wouldn't sweat anything yet. I have the same car and my UOAs hav been consistent, and that's what we want. Consumption is likely a byproduct of hard driving (though even during race season my car only consumes about 1qt every 5k).

Don't run the Syntec 5w40 again, there are far better oils for the same money. The GC should do well. M1 0w40 is a good alternative. If you have deeper pockets, plenty of mail order alternatives too.

PS, post a photo, you have a rare car!

 

[gdawga4]

Originally Posted By: addyguy
If it's been driven really hard, the rings are worn, pure and simple.

During the summer, I'd try a 50wt., just to see what happens - 15W-50, 5W-50, 20W-50....just to see if viscosity is the only thing that changes it.


Yeah, I have no idea how the PO drove it. I'm a spirited driver but don't beat on it.

 

[cchase]

IIRC if adding oil boosts compression, the rings are shot.

 

[ARCOgraphite]

That BP 5w-40 is formulated like a diesel oil est visage de rigueur e E.U. huile. UNfortunately, most people never have the time or space to regularly run these high HP engines as hard as they require and they get gummed and carboned up. I assume this engine has a complex PCV that has been given a good bill of health?

 

[dparm]

For reference, here's my car at about the same mileage through the OCI.

And here it is before that when I swapped out the Lubro-Moly Synthoil Premium. As you can see, the LM doesn't handle race use quite as well.

 

[gdawga4]

Originally Posted By: dparm
I wouldn't sweat anything yet. I have the same car and my UOAs hav been consistent, and that's what we want. Consumption is likely a byproduct of hard driving (though even during race season my car only consumes about 1qt every 5k).

Don't run the Syntec 5w40 again, there are far better oils for the same money. The GC should do well. M1 0w40 is a good alternative.


Hey, I figured you would chime in at some point

I'm over on EA and AZ but don't post too much (mostly on QW). I was using up my Syntec 5w40 stash I had and just wanted to see if it would change anything (figured that's what was used previously as the PO serviced it at the dealer). GC is my go to oil for our cars unless they're out then it's M1 0w40. I'll be curious to see what the UOA looks like after this run.

 

[dparm]

Pull a sample at the halfway point and post it up. I did that with the Motul because I was curious how it had handled the previous race season...as you can see it looked great. The LM was really breaking down after racing.

 

[gdawga4]

Originally Posted By: ARCOgraphite
That BP 5w-40 is formulated like a diesel oil est visage de rigueur e E.U. huile. UNfortunately, most people never have the time or space to regularly run these high HP engines as hard as they require and they get gummed and carboned up. I assume this engine has a complex PCV that has been given a good bill of health?


Thanks for reminding me about the PVC, forgot to mention that. It's good and even ordered a new one. I also put in a catch can to see how much oil was getting collected and it's not much. It's definitely going out the exhaust (no external leaks either).

 

[gdawga4]

Originally Posted By: cchase
IIRC if adding oil boosts compression, the rings are shot.


Either shot or really stuck lol

 

[ARCOgraphite]

Originally Posted By: cchase
IIRC if adding oil boosts compression, the rings are shot.
No, adding top oil always boosts compression. The question is by how much. Plus you have to comp test with a hot motor and the throttle body open. Most guys forget this. Add VVT and you can get funny results if cams are phased at high overlap for low compression easy start/crank. Car are complex this aint the fitties.

 

[cchase]

Originally Posted By: gdawga4
Originally Posted By: cchase
IIRC if adding oil boosts compression, the rings are shot.


Either shot or really stuck lol


True, although carbon on top of the pistons is normal for every engine and doesn't necessarily mean the rings are also carboned up.

 

[dparm]

Guys, relax about his motor. There's a very tiny percentage of owners who got scored pistons (they're quite vocal though). It's total fearmongering on the Audi forums. I think I've seen like a dozen people ever say they had this problem out of thousands of cars produced. So far he's not really giving us any conclusive evidence it's affecting him. In fact, the borescope results sound like the car is fine.

If he's regularly changing the oil I think the car will be okay.

 

[cchase]

Originally Posted By: dparm
Guys, relax about his motor. There's a very tiny percentage of owners who got scored pistons (they're quite vocal though). It's total fearmongering on the Audi forums. I think I've seen like a dozen people ever say they had this problem out of thousands of cars produced. So far he's not really giving us any conclusive evidence it's affecting him. In fact, the borescope results sound like the car is fine.

If he's regularly changing the oil I think the car will be okay.


There's something unsettling about the concept of 7 qts of make-up oil in under 3000 miles and the phrase "the car is fine" to me.

 

[gdawga4]

Originally Posted By: dparm
Pull a sample at the halfway point and post it up. I did that with the Motul because I was curious how it had handled the previous race season...as you can see it looked great. The LM was really breaking down after racing.


Will do Dan. I'm not too worried about the wear yet till I get some more UOAs and see what the trend is.

Here are some pics...sorry not the best as they were taken from my phone.

 

[gdawga4]

Originally Posted By: cchase
Originally Posted By: gdawga4
Originally Posted By: cchase
IIRC if adding oil boosts compression, the rings are shot.


Either shot or really stuck lol


True, although carbon on top of the pistons is normal for every engine and doesn't necessarily mean the rings are also carboned up.


I know some carbon is normal but these are literally covered in a layer of carbon (can't even see the piston surface). In comparison, my '05 1.8T with 145k had very little carbon on the pistons.

 

[dparm]

Originally Posted By: cchase
Originally Posted By: dparm
Guys, relax about his motor. There's a very tiny percentage of owners who got scored pistons (they're quite vocal though). It's total fearmongering on the Audi forums. I think I've seen like a dozen people ever say they had this problem out of thousands of cars produced. So far he's not really giving us any conclusive evidence it's affecting him. In fact, the borescope results sound like the car is fine.

If he's regularly changing the oil I think the car will be okay.


There's something unsettling about the concept of 7 qts of make-up oil in under 3000 miles and the phrase "the car is fine" to me.




[censored], that was 6.75qt of makeup...I totally just noticed that. I thought it was 0.75qt.

 

[gdawga4]

Originally Posted By: ARCOgraphite
Originally Posted By: cchase
IIRC if adding oil boosts compression, the rings are shot.
No, adding top oil always boosts compression. The question is by how much. Plus you have to comp test with a hot motor and the throttle body open. Most guys forget this. Add VVT and you can get funny results if cams are phased at high overlap for low compression easy start/crank. Car are complex this aint the fitties.


Compression test was done with a hot motor and the throttle body was kept in the open position

I'll try and find the numbers.

 

[gdawga4]

Originally Posted By: dparm

[censored], that was 6.75qt of makeup...I totally just noticed that. I thought it was 0.75qt.


lol, I wish it was 0.75 qts!