Best oil to alleviate excessive carbon build up

[ikolbyi]

My 2008 Audi A6 3.1L (3.2) FSI Quattro is experience on-going excessive carbon buildup on the intake valves (slightly different story than most posts)
Oil change interval is every 5,000 miles - not every 10,000 as manual states.
Driving habit - 600 miles per week, average speed 70-90 mph in North East.

Summary of events:
* While using Castrol Syntec 5w-40 oil
-- with Exxon 93 octane fuel, miss-firing begins every 1,000 miles after valve cleaning and requires valve cleaning approximately every 4,500 miles due to violent shaking and permanent CEL.
-- with Shell 93 octane fuel, miss-firing begins every 1,000 miles after valve cleaning and requires valve cleaning approximately every 4,500 miles due to violent shaking and permanent CEL.
(Chevron Tektron does not really help when used every 3,000 miles)

* While using Mobil 1 0w-40 oil
-- with Exxon 93 octane fuel, miss-firing begins every 4,000 miles and requires valve cleaning approximately every 7,000 miles due to violent shaking and permanent CEL.
-- with Shell 93 octane fuel, miss-firing begins every 4,000 miles and requires valve cleaning approximately every 7,000 miles due to violent shaking and permanent CEL.
-- with Sunoco 93 octane fuel, automobile requires a manual valve cleaning at 10,000 miles. The automobile does misfire, but the event is so minor, it is a non-issue. However, I have noticed decreased fuel efficiency since the move from Exxon and Shell and when I hit 12,000 miles (oil change interval is 5,000 miles), the miss-firing becomes the most violent, as if the engine will drop on the street.
(Chevron Tektron does not really help when used every 3,000 miles)

* While using Mobil 1 5w-40 ESP M oil
-- experienced similar results to Castrol Syntec. I thought perhaps the low ash count would help.

My question is, what is your recommendation in my situation and what oil should I use to help mitigate the issue since it does have an impact?

My next trial and error is Mobil 1 5w-30 ESP, but is their something I should try first? My goal is to see if the miss-firing can hold off until 15,000 valve cleaning intervals, not less than 10,000.

 

[demarpaint]

Have you tried treating the fuel? Red Line FI cleaner comes to mind it can be used as a maint dose, continuously? MMO at a rate of 4 ounces/10 gallons of gas comes to mind as well. I'd check out the possiblility of installing an Inverse Oiler.

 

[ikolbyi]

Yes, I have used Audi branded fuel additive with no noticeable improvement, and presently use Chevron Textron with very slight improvement. The FSI engines by Audi are direct-inject gasoline engines so the intake valves are never cleaned by fuel, therefore any fuel additive does not make contact with the intake valves until after it has been burned in the chamber. Different types of oil do alleviate the problem, but not solve. I'm looking at the best way to approaching that. So far, the factory fill (and tried a 2nd time by me) Castrol Syntec 5w-40 performed the worst causing my valves to gunk up the fastest.

 

[demarpaint]

Look into an Inverse Oiler. I had a feeling these engines were DI which seems to be a major problem, by design. An Inverse Oiler might be the ticket for you.

 

[ac_tc]

mopar combustion chamber cleaner.
The one in a spray can, follow the instructions.

 

[Bluestream]

Have you contacted your dealer about this issue?

 

[bluesubie]

And does your dealer have a regimen for dealing with the issue? Have you considered a catch-can? And last question; have you read this thread?

From what I've read on an Audi forum, Renewable Lubricants Inc isn't the long term solution folks once thought it was. It only delays the inevitable.

-Dennis

 

[ikolbyi]

AoA (Audi of America) is well aware of my situation, the answer is - deal with it. (this was a 1.5 year 'discussion' with them).

Car runs fine (no CEL but does miss-fire)as long as I have the valves manually cleaned every 7,000 miles, therefore they consider it maintenance. CEL comes on about every 7,000, sooner if I use Castrol Synctec motor oil (factory fill-dealer default)

Seafoam did not work when I performed it twice (perhaps I used the wrong vacuum hose?), the only thing that does is BG injection kit or crushed walnuts (performed by dealer).

At this point I'm wondering if a lighter weight oil (30) would help under the impression the deposits would hopefully burn off. As mentioned earlier, I did see noticeable improvement when switched from 5w to 0w within 40 weight. Thoughts on this?

 

[Rob_Roy]

You have already tried the obvious...a low ash engine oil, different fuels, and some fuel treatments. What does Audi have to say about this problem?

The only thing I can think of beyond some sort of inverse oiler like mentioned above...is a gasoline treatment that you run all the time. Some gasoline treatments are intended to mainly clean injectors, others have much more of an oil base and are intended to remove carbon and provide lubrication. Texas Refinery's DZL-LENE XL 10, Lubrication Engineer's L-X 2300, and Primrose Protect-O-Lube 400 come to mind. Schaeffer's Neutra 131 uses a different type of chemistry, but it is also very effective at removing carbon.

 

[UG_Passat]

All the manufacturers that use GDI technology has said FU to the customers.

I started using LC-20 additive with my oil (Shell Rotella T6), hoping it might control it on my 2.0T.

(RLI gets quite pricey....in times of penny pinching).

 

[demarpaint]

I read a few cases where an Inverse Oiler has helped with the situation. It is certainly worth a try. I wish I could remember where I read it. I'd go to the MMO forum and ask there. The more I learn about these DI engines the happier I am I don't own one.

 

[R2d2]

Manually cleaning the valves every 7k is insane. I'd sell the car as soon as possible, to think I considered an A6.

 

[Bill in Utah]

Originally Posted By: demarpaint
The more I learn about these DI engines the happier I am I don't own one.


I've said that since day one. When NORMAL engines have been getting the same MPG in ACTUAL conditions no need in my use to have a DI motor.

I'll stay far away from one as long as I can.

Bill

 

[Finklejag]

How are you cleaning the valves? Maybe try BG's new GDI service. It will run about $150.00.

BG GDI Service

If you want to spend the money. Try Red Line 5W-40. Myself and a few other VW DI owners use it. It's been holding its flashpoint and staying a 40 weight for the whole oil change interval. It has a Noack of 6%. That's about half what other VW 502 spec oils on the market have. It will help with evaporation blow-by.

 

[ikolbyi]

Originally Posted By: bluesubie
And does your dealer have a regimen for dealing with the issue? Have you considered a catch-can? And last question; have you read this thread?

From what I've read on an Audi forum, Renewable Lubricants Inc isn't the long term solution folks once thought it was. It only delays the inevitable.

-Dennis


bluesubie, thank you for the URL thread, I have seen similiar ones but not as detailed as that one - it was a good read. The problem outlined is exactly what I am experiencing, the only difference is the frequency. I seem to be impacted much more than the average driver. The dealership and AoA do not know why and have tried replacing parts with no success (injectors, coils, etc...). But then again they didn't expect that (nor did I) to fix the issue, they performed the work for the sake of showing effort. One guess why I experience it more frequent is I'm more of a spirited driver and push the engine. So now I'm back to where I started, cleaning the valves with BG intake solution or blasting the valves with crushed walnuts works, but my wallet is feeling the pain. My goal is to have this service performed every 15,000 miles not every 7,000. Mobil 1 0w-40 was a vast improvement over Castrol Syntec 5w-40 and Mobil 1 5w-40 ESP M. So far I've seen takers on Mobil 1 5w-30 ESP and Red Line 5w-40. Also available in my area is Shell Rotella 5w-40 and Amsoil 5w-30 and 5w-40 Euroblend. What should I attempt next?

 

[demarpaint]

Originally Posted By: Bill in Utah
Originally Posted By: demarpaint
The more I learn about these DI engines the happier I am I don't own one.


I've said that since day one. When NORMAL engines have been getting the same MPG in ACTUAL conditions no need in my use to have a DI motor.

I'll stay far away from one as long as I can.

Bill


Exactly how I feel. At the moment they are a problem in need of a solution.

 

[MaxZX]

I don't know if this will be of use here, but the best oil and fuel system cleaner I have used, bar none, is Kreen. There are a few threads about it here in he Oil Additive section. It's anectdotal 'evidence' at best, but it sure seems to have cleaned up my daughter's and mine engines nicely. In fact, after dosing my fuel with it, the gas gauge moves around a lot more going up and down hills. Could be wrong, but I'm taking that as a sign it did something (hopefully cleaning!). My car has a GM 3800 with 127k miles, ran great before but not it hums very quietly. User Trav here seems to know his stuff about engines and he endorses it highly.

order from www.kanolabs.com, 12.50 a quart delivered, plus you get a free can of Kroil (think PB Blaster on steroids).

 

[CATERHAM]

To remedy I'd first convert to a catch can system to eliminate the crankcase ventilation part of the problem completely. That should largely remedy the DI intake valve build-up problem. Any further build-up would be the result of oil getting past the intake valve seals.

Regarding the oil choice, I find it interesting that M1 0W-40 has shown the lowest rate of carbon build-up of the oils you have tried. You could try RLI but I'd do some research on the lowest SAP's oil's available.

 

[jaj]

There are no fuels or fuel treatments that will help because the fuel is injected after the intake valve.

Oil treatments containing volatile components could easily make things worse because they increase the amount of entrained goop going through the crankcase ventilation system and creating deposits on the intake valves.

The three things that might make a positive difference are:

- low volatility engine oil. Renewable Lube products have a good reputation in this regard.

- engine oil that cleans the ring area and improves the quality of the ring seal to reduce blow-by. Again, Renewable Lube products have a good reputation in this regard.

- a catch-can/filter in the ventilation return line that removes more of the entrained volatile components before they get to the intake valves.

Other than that, there isn't much you can do. Some DI engines carbon up the valves and some don't.

 

[UG_Passat]

Originally Posted By: demarpaint
Originally Posted By: Bill in Utah
Originally Posted By: demarpaint
The more I learn about these DI engines the happier I am I don't own one.


I've said that since day one. When NORMAL engines have been getting the same MPG in ACTUAL conditions no need in my use to have a DI motor.

I'll stay far away from one as long as I can.

Bill


Exactly how I feel. At the moment they are a problem in need of a solution.


Buy a Lexus, but not a ES/RX. Their direct injection engine also runs port injection for low & medium loads.