N54 engine ownership guide

[Busterboo]

Walnut shell is only a harder medium than the carbon deposits though, it’s not as hard as the steel & alloy within the combustion chamber. After all when it’s blasted into the intake ports it doesn’t harm the valves or port in anyway does it?
Rob

The danger lies in the failure to remove any remaining abrasive medium and the combined residue of medium & 'dirt' after cleaning. This applies to all abrasives, of course, and not only walnut shell. However, if a car owner's happy the techie's doing this, fine.

That said, the use of walnut shell was discontinued by the aviation industry a long time ago (or so my cousin, who works for R-R, has told me).

[enzed4]

Seriously, a quick search found many references to BMW dealers carrying out this service. I read that to mean it is BMW approved/recommended.

By "dealers" do you mean dealers who sell used BMWs? Or ADs - dealers authorised by BMW to import & sell new cars?

I'm not familiar with the difference. Here a 'BMW dealer' is a BMW approved sales (and usually maintenance) facility. Anything else is just a car dealer regardless of the brands they sell. I wasn't aware there's a difference so when I read BMW dealer I took it to mean BMW approved.

[MrPT]

How about a softer nut, e.g. cashew?

[Busterboo]

How about a softer nut, e.g. cashew?

Now you're taking the pith.