[dieselgg]

I found these tips from another BMW forum on preventing carbon build-up on the back of the valves. Providing it as information, hoping it can help anyone who shares this concern. I don't think I am allowed to provided the link but I copied and pasted the post for from the member who posted it on that forum.

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To all of you. Take this from a guy who had an N54 with 70k plus miles on it. I dealt with all of the symptoms you guys described and think I have reasonably figured out how to work around it. First, you MUST drive the car at sustained high RPM's at least once or twice a month. I had all of the symptoms you guys have described in this thread and they started around 30k miles. By 50k miles the engine ran better than at 30k miles and I am about to explain how I accomplished that without the shop ever looking at the motor.

1) At least once a month and preferably twice a month take the car onto an interstate or high speed road. Warm up the motor at low RPM's and then put car in 3rd gear and do 65-70 mph. It will turn about 4500 rpms. Drive like this for a good 20-30 minutes. You will notice that the engine pulls harder and runs better. This method helps to burn off that oil and carbon on the back of the valves, but this only works if you do it often and before the buildup becomes an issue.

2) Use BMW fuel system cleaner plus every 5k miles. It does not wash over the valves, but the injectors on this car do seem to foul easily. In addition, stick to BP/Top Tier gas. I have tried every brand of gas and I have the best luck, in the N54, with Shell, Chevron and BP (in that order).

3) Use different brands of gas every other tankful. If you like to use one brand repeatedly then after 5 tanks of that brand switch to another brand for 2 tanks. This helps to get rid of gas additive buildup on the injectors...it does happen and some of these stumbling and hesitation problems are not carbon buildup but rather injector buildup.

4) The obvious. Change the oil every 7500 miles or less. It does help.

Trust me guys. I learned this stuff from a master BMW tech/foreman who has been working on these cars his whole life. While direct injection is newer technology, he knew enough about it to counteract the carbon buildup problem. He drives an N54 and has 145k miles without ever doing a carbon cleaning. He does exactly what I do and I know other people with high mileage N54's that run great following this routine. I sold my N54 with over 70k miles and the used car manager said it was one of the best, if not the best, running N54's he has driven that was out of warranty. I told him what I am telling you and explained how this ritual does work. I plan to do the same to my N55. Lastly, those of you that drive slow city driving...this engine will hate you and punish you. Make sure you do what I suggested even more so than the highway commuters. The engine needs to get hot to burn off that oil blowby.
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[bumere90]

With direct injection, it is almost impossible to prevent carbon build up.

[dieselgg]

I have googled many times this topic and read many, many posts and this is the first post I found that seems to offer a glimmer of hope, which is why I posted it. All the other posts discuss using Techron, Seafoam (which don't work). The OCC does a little but not much ..... so I don't think I really need the Noob intro.

[MWhy]

Kinda like the old school "burning off the carbon" they used to do on old American muscle cars. Gotta open it up once in a while. Couldn't hurt anyway. I doubt many of us would be averse to driving hard and fast by "prescription."

[morphius909]

SEAFOAM??

[project6]

Originally Posted by morphius909

SEAFOAM??

Yes, Seafoam! Old school engine cleaner, carburetor gunk killer, cleans out your injectors very nicely, too.

[Surly73]

Originally Posted by project6

Yes, Seafoam! Old school engine cleaner, carburetor gunk killer, cleans out your injectors very nicely, too.

When you do what with it? Seafoam in your fuel is not going to anything for N54 carbon build up because the fuel doesn't touch the valves. If you inject it in the air stream, it's rarely going to spread out and evenly decarbon all of the intake ports on the head.

If I had a DI engine I would probably be DIYing the carbon build up by rigging up a system to inject something like Amsoil Powerfoam into the intake manifold. Alternatively the IM could be removed every time and you could spray it into the ports on the head, right onto the backs of the valves.

I read an article posted by someone, I think a Caddy owner, who installed a fitting into each runner of the IM so that he could inject Powerfoam on a regular basis for just this reason. With injection sites close to the head you're sure to fill the ports.

The instructions on the can of Powerfoam say that you can fill the entire intake manifold through the throttle body (obviously written from a traditional engine design standpoint), let it sit, start it up and blow all the crap through. It'll make a cloud of smoke, but so will seafoam.

The problem with Seafoam is that it's a liquid. Even when used through vacuum lines in the intake it's difficult to get it to reach everywhere evenly. You can often end up decarboning just one or two pistons that the liquid reaches in the air stream. It's not like there's a lot of airflow sitting in your driveway under no load goosing the throttle either. Powerfoam foams up and should fill the entire intake manifold and the ports on the head. in theory.


EDIT:
This is the kind of build up you're talking about. With the intake manifold removed you can see the site of the build up. I believe the top picture was cleaned with Amsoil Powerfoam.

EDIT:
Found the article I was thinking of: here.

[tehron]

Bump awesome right up to the OP.

I drove an rx8 before my n55 135i, and rotaries are notorious for carbon buildup. Only way to rid it is seafoam, tear down, or drive it like you stole it.

When it idled rough I gave it a good beating to 9.5k RPMs and that seemed to do the trick after a few hard runs.

[BMDoublYou]

Sooo.. the alternative to paying about $400 once every 40/50k miles, is spending 300/400 dollars a year on fuel additives/intensive oil changes/burning more fuel drive in 3rd on the highway...

[norsairius]

Originally Posted by BMDoublYou

Sooo.. the alternative to paying about $400 once every 40/50k miles, is spending 300/400 dollars a year on fuel additives/intensive oil changes/burning more fuel drive in 3rd on the highway...

I had a VW GTI a while back which had a DI 2.0L turbocharged motor. Seafoam was really popular among enthusiasts in that crowd. I believe they got it to hit the intake valves by having it sucked in via an intake hose somewhere, I forget where. Seemed to work all right, but I never did it. I got my GTI up to about 60k miles and didn't notice any issues due to carbon buildup. Just drove it hard when I could. I never used any fuel additives and whatnot. Just regular maintenance, never had a problem. I still miss that car sometimes, haha.

In general, I do believe that the occasional "Italian tuneup" works for helping with the carbon buildup, but I also believe it's something that will inevitably need to be dealt with via a more thorough cleaning process. Driving the car hard is at least fun, right?

I agree with what you're saying though. I'd go the route of paying for a more thorough cleaning on a more infrequent basis and just drive the car hard from time to time rather than get more frequent oil changes and putting additives in to the car all the time.

That said, I don't have this concern in my car since I drive a lowly 328i, but if I had a DI BMW motor in my car, I don't think I'd put too many additives in it. There's plenty in gasoline already and the engine was designed to run with that for the vast majority of the time.

[Augster]

Originally Posted by BMDoublYou

Sooo.. the alternative to paying about $400 once every 40/50k miles, is spending 300/400 dollars a year on fuel additives/intensive oil changes/burning more fuel drive in 3rd on the highway...

Yea, that's why I'll stick to DIY with my shop vac and el cheapo sand blaster ala Harbor Freight jury rigged to a genuine BMW N54 Vacuum Blaster Adapter with Blasting Wands. The hardware is just a one-time expenditure; may be a couple Washington's at most, while a 25 pound bag of walnut shells costing $25 will probably last at least two, if not more, valve cleaning sessions. Intake manifold gasket set costs ~$35 from your favorite BMW e-tailers.

So amortized over the 100,000 miles I expect to own the car before eventually selling it, estimating at least three valve cleaning sessions, comes out to about $110 maximum per job. I currently drive the car about 8,000 miles a year, which stretches out the duration of my ownership to about 12 years, or ~$28 per year on valve cleaning.

But I use the shop vac and sand blaster for other jobs so those equipment costs really can't be claimed against maintaining my 335i so my actual annual maintenance costs for valve cleaning are much lower.

[BMDoublYou]

Originally Posted by Augster

Yea, that's why I'll stick to DIY with my shop vac and el cheapo sand blaster ala Harbor Freight jury rigged to a genuine BMW N54 Vacuum Blaster Adapter with Blasting Wands. The hardware is just a one-time expenditure; may be a couple Washington's at most, while a 25 pound bag of walnut shells costing $25 will probably last at least two, if not more, valve cleaning sessions. Intake manifold gasket set costs ~$35 from your favorite BMW e-tailers.

So amortized over the 100,000 miles I expect to own the car before eventually selling it, estimating at least three valve cleaning sessions, comes out to about $110 maximum per job. I currently drive the car about 8,000 miles a year, which stretches out the duration of my ownership to about 12 years, or ~$28 per year on valve cleaning.

But I use the shop vac and sand blaster for other jobs so those equipment costs really can't be claimed against maintaining my 335i so my actual annual maintenance costs for valve cleaning are much lower.

I saw your write up a while back, excellent and definitely what I will be following when I do it in the spring, thanks for taking the time to create such a good guide

[stanlalee]

Originally Posted by norsairius

I had a VW GTI a while back which had a DI 2.0L turbocharged motor. Seafoam was really popular among enthusiasts in that crowd. I believe they got it to hit the intake valves by having it sucked in via an intake hose somewhere, I forget where. Seemed to work all right, but I never did it. I got my GTI up to about 60k miles and didn't notice any issues due to carbon buildup. Just drove it hard when I could. I never used any fuel additives and whatnot. Just regular maintenance, never had a problem. I still miss that car sometimes, haha.

In general, I do believe that the occasional "Italian tuneup" works for helping with the carbon buildup, but I also believe it's something that will inevitably need to be dealt with via a more thorough cleaning process. Driving the car hard is at least fun, right?

I agree with what you're saying though. I'd go the route of paying for a more thorough cleaning on a more infrequent basis and just drive the car hard from time to time rather than get more frequent oil changes and putting additives in to the car all the time.

That said, I don't have this concern in my car since I drive a lowly 328i, but if I had a DI BMW motor in my car, I don't think I'd put too many additives in it. There's plenty in gasoline already and the engine was designed to run with that for the vast majority of the time.

the FSI/TSI seafoamed because the intake manifold was 10x harder to take off to manually clean the valves than these cars. I'm of the philosophy if there are no symptoms its just a waste of time cleaning intake valves with DI as they will just get the same way in no time. My FSI has 128K miles, FBO including K04 turbo and I NEVER had the valves cleaned or related issues. I may do it with this car since its like half the price (because of not only the added labor of taking off the intake manifold but because 90% of the VW shops are stuck on manual removal instead of of walnut blasting which again adds 10x the labor).

[Benstuck]

Originally Posted by tehron

Bump awesome right up to the OP.

I drove an rx8 before my n55 135i, and rotaries are notorious for carbon buildup. Only way to rid it is seafoam, tear down, or drive it like you stole it.

When it idled rough I gave it a good beating to 9.5k RPMs and that seemed to do the trick after a few hard runs.

I had a 05' RX-8 and I redlined it at least 10 times each time I drove, that engine was just so easy to rev! I miss that car, so light and agile, but not the best fuel economy.

[Alohaaaaa]

I drove mine at 4500 revs on the way home today... It just felt goofy as hell, but I forgot how sick the throttle response was! One tap of the gas and I was off to the races!

[1QuikWS6]

Use BMW fuel system cleaner plus every 5k miles

All the other posts discuss using Techron, Seafoam (which don't work).

You 1st state to use BMW fuel system cleaner - then later state that Techron doesn't work

The BMW fuel system cleaner IS Techron - just rebranded for BMW...

[Augster]

Originally Posted by BMDoublYou

I saw your write up a while back, excellent and definitely what I will be following when I do it in the spring, thanks for taking the time to create such a good guide

Although I'd love to have discovered this lower cost method of valve cleaning, I have to give credit to whom truly deserves it: e90man over at N54Tech in his reveal thread DIY Cheap N54 Walnut Shell Blasting. He even rents out the specialized BMW equipment for $40 from Alabama shipped anywhere in CONUS; not a bad price actually, considering the periods of backordered status of the components and shipping costs.

[norsairius]

Originally Posted by stanlalee

the FSI/TSI seafoamed because the intake manifold was 10x harder to take off to manually clean the valves than these cars. I'm of the philosophy if there are no symptoms its just a waste of time cleaning intake valves with DI as they will just get the same way in no time. My FSI has 128K miles, FBO including K04 turbo and I NEVER had the valves cleaned or related issues. I may do it with this car since its like half the price (because of not only the added labor of taking off the intake manifold but because 90% of the VW shops are stuck on manual removal instead of of walnut blasting which again adds 10x the labor).

Didn't know that the intake manifold was so difficult to take off. I just didn't read up that much on the reasoning for going Seafoam, but that definitely makes sense.

I agree with you though. If there's no symptoms, why worry? Drive the car hard and maybe you'll knock or burn off some of the carbon deposits, but otherwise if walnut shell blasting is relatively easier to do for this car, then just go that route when you need it or even at certain mileage intervals if you want. That's the route I'd go anyway for when I get a car with a DI motor again.

[ezmaass]

This is just silly.

If you drive for 20 - 30 minutes twice a month at 4500 RPM, you're going to burn a lot of excess gas unnecessarily. Gas isn't cheap these days. You may end up burning a few hundred dollars EXTRA in gas for the year if you stuck to this behavior year-round. No less, you're putting excess wear on the engine keeping it in low gear while driving at highway speeds.

Combine that with the other treatments prescribed, such as fuel cleaner every 5k miles plus changing your oil TWICE as frequently as needed, and you're into some pretty good bills for the year... all to avoid what? A walnut blasting that costs $400 every 2 or 3 years??

I owned my 335 for 6.5 years, and I never did any of the above - honestly, not even a walnut blasting (although it may have been coming due by the time I sold). I changed the oil when the car said it was time, I never put additives or cleaner into the tank, and I just followed the standard maintenance schedule. As for driving, I drove the car the way it was intended to be driven - no ridiculous stuff like putting it in 3rd gear for 20 or 30 miles on the highway... EVER. I drove it on the highway regularly, and it saw nice spirited drives. I brought the car to redline at least a few times during each highway drive (just for the fun of it, not for "maintenance"), and I otherwise drove pretty casually elsewhere.

The above-mentioned "schedule" of maintenance makes no sense. There's no ROI in it, either. The cost of doing all of the above versus a walnut blasting every few years just doesn't equal out. You're going to spend more money and put more wear on the car. Just drive the car the way it was intended, and maintain it per BMW's specs, and you'll be just fine. Suggesting that anyone needs to follow such a routine would also be equivalent to saying that BMW doesn't know what the hell they're doing in the manufacturing or suggested maintenance routines for their own cars.

[Blackhawk36]

Fools errand. You can't prevent it carbon build up in the N54 especially with additives. The reason some of you don't notice it is because it sneaks up on you. Idle slowly deteroirates and mid-range power and smoothness gets worse. Most people accept it as normal and keep on driving. It doesn't throw any codes either. And cruising around town or on the highway there are no symptoms. Physical intervention (walnut blasting or solvents and little brushes) is the only thing that will fix the problem.

[_Sinister_]

Sweet write up OP thanks for the advice

[JAYHEF]

Any idea how often you should get the valves cleaned to stay out of trouble and maintain optimal operation condition?
Asked my dealer, the service manager told me that BMW didn't recommend preventive valve cleaning but he also said (from past experience at a GM dealership) that 50,000Km was probably a good idea.

Anybody here doing regular walnut shell blasting on their intake valve? if so at what interval?

Thanks