[tony20009]

I keep seeing, of late, folks talking about walnut blasting. I've heard of this as a treatment for rust. I just can't imagine that our cars are at the point of rusting quite yet. Can someone please explain what the walnut blasting is used for, if not as a way to address flaws in the car's body and paint?

Thanks in advance.

[straightcashhomie]

Walnut blasting is cleaning the intake ports.... Lol search.

[thenewrick]

it cleans carbon buildup on the intake valves so air flows into the motor a little easier

[tony20009]

TY

[jmarino21]

The reason people are having it done is because with direct injection fuel systems, it is the best way to remove carbon deposits from the intake valves. A fuel injector cleaner such as Techron or Redline SI-1 only cleans this area on port fuel injection vehicles. They still work on the injectors themselves and inside the combustion chamber though.

If you have rough idle, sluggish throttle or notice diminished performance or gas mileage you might want to check it out. It's not part of the maintenance program but you may be able to get it covered under warranty.

The RS4 is notorious for this buildup problem. And they can't be walnut blasted, the engine has to be taken apart. Audi fail.

[AzureHaze]

Originally Posted by jmarino21

The RS4 is notorious for this buildup problem. And they can't be walnut blasted, the engine has to be taken apart. Audi fail.

Eeeeek! Guess the Quattro GmbH engineers didn't think that through.

[Cali*335i]

Originally Posted by jmarino21

The reason people are having it done is because with direct injection fuel systems, it is the best way to remove carbon deposits from the intake valves. A fuel injector cleaner such as Techron or Redline SI-1 only cleans this area on port fuel injection vehicles. They still work on the injectors themselves and inside the combustion chamber though.

If you have rough idle, sluggish throttle or notice diminished performance or gas mileage you might want to check it out. It's not part of the maintenance program but you may be able to get it covered under warranty.

The RS4 is notorious for this buildup problem. And they can't be walnut blasted, the engine has to be taken apart. Audi fail.

Great info I been meaning to get mine done I have around 56k miles and I'm sure it's about that time. At some points my cAr does well a bit sluggish.

[E90gone]

When you guys say sluggish, do you mean you hit the gas and it doesn't go any where and then you push a little and I do mean little harder and all of a sudden the car start to move forward but faster then you wanted. I feel like I can push the gas pedal down about a 1/2" and the car barely moves but a get to a point and then vroom it starts move rather quickly.


Is that the sluggish feeling? I don't have a rough idle and not sure if the car is down on power as I just bought it. But this car seems to be the hardest to control the gas pedal on out of every car I have ever driven and owned.

[thenewrick]

That's just turbo lag an it's normal. Cleaning intake valves can increase responsiveness of the throttle very minimally though.

For responsiveness you'll want to stay above your peak torque curve which is around 4k rpm roughy. If you're in an auto you'll have much less control with this.

[E90gone]

That's some crazy turbo lag then. My eclipse was nothing even close to that. It is an auto so maybe that has something to do with it too.

[Wires]

OP, walnut blasting is also used to remove paint/rust (here it's about cleaning out intake carbon most of the time though).

Sandblasting body panels ends up etching pits into them, so that's why walnut shells are used.

[Titanium3er]

IMHO it's absolutely necessary on the 335, at least the N54 engine, every 50-60k. If you search the forum you'll see before and after pics of the intake valves that prove this.

I had mine done under CPO around 62k and the difference is night and day. Before the car had a very rough idle and the power cut out under heavy load. Now I experience neither of those symptoms.

[123Britt]

Following the DIY N54 Walnut Blasting -- I have just completed cleaning all 6 cyl. Now -- tomorrow I will try to remember how to put it all back together. I took it all apart in 4 hrs Friday night. Spent another 7 hrs with many back breaks for the actual cleaning process. Even with Walnut blasting there is a lot of scrubbing and gunk soaking to get good results similar to on-line posted pictures.
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Car has 85k and idles funny and skips around at 2k rpm (most noticeable). Dealer recommended the work at $1000. SO I DIY for $300 including the price of compressor.
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My BMS OCC had just a little coating of oil. I also have on order RB PCV.
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You have to love the N54 -- I think BMW should pay for the service - I will report back next week with results.

[cookie munsta]

im such a newb, but should I worry about this even if I drive a ...328i?

[123Britt]

328i -- if 4cy Turbo -- this does apply. In-Line 6 -- NO.
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Results after cleaning -- smooth and steady idle. Smooth linear acceleration and no more stumbling at 2k rpms or under heavy load. A really worth while project -- highly recommended for all. I'll bet most of my cars build-up occurred with the original owners 2 oil changes for the first 32k. I took ownership and have changed oil every 5k since.
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Next project = Water pump and Thermostat ~ I got the parts from Tischer but ESC Tuning has the non-BMW stamped parts for less.

[tunachris]

I just had it done today at about 52k. Also had the plugs changed. Did both 2 years ago at 25k. Much better response now, and no worries for another 25 thousand miles.

[Three_thirty_I]

I've seen many pics of how clogged up DI engine intakes can become! It's quite scary especially if some of this carbon breaks off and gets ingested - but from what I've read, this usually only has to be done every 50k km or so. I also hear that having an oil catch can does help by preventing blow by oil going back to the intakes (so no oiliness for the carbon to adhere to, or far less)...

[jla57]

My first post,
(Just an FYI for others who may be in a similar spot with their 35i.)

I have taken my 2008535i in to the dealer for a fourth time. Idle hiccups when cold, hiccups sometimes under load/passing. And, on occasion, get an engine light with the message "reduced engine power". They have replaced a few injectors, this and that. Say that BMW engineers are blaming bad fuel in the US causing carbon build up on the injectors. This is the message I received from the dealer:
Everything on the vehicle has checked ok. The tech has been directed that the vehicle has possible carbon build up on the valves which is characteristic of some direct injection engines in BMW, Audi, Porsche etc. The dilemma we are now faced with is that carbon build up is not a warrantable repair. I talked to "name" yesterday and he approved for the tech to expose the valves for inspection to determine if this is truly a carbon issue or not in which the tech has found carbon build up on all the intake valves (see attached picture). To correct this we would have to perform what called walnut blasting to remove the buildup. This procedure will take most the day to perform and cost $967.88 parts and labor. I can’t say this will be the price you would have to pay as I have not yet had a chance to talk to "name" about discounting this price in which I know he will give you some assistance in this repair. Let me know if you have any other questions.
Note the word used is "possible". Which means that I would pay for the parts/labor and I am sure would not be refunded if the cars still exhibits the issues. Guess I don't feel "taken care of" since this process is just hit or miss and now I get popped for the guessing game.

Later,
jla57