Originally Posted by mountainhorse

Great post !

Some thoughts... Once you've done the walnut shell blasting or other mechanical cleaning.... Follow up with the CRC or other more professional strength cleaners like the BG-GDI cleaners. Since the valves are closed during the Walnut-shell blasting service... it would be a good idea, IMO, to do a thorough intake/intake-valve cleaning chemical treatment... this will do a finish clean of the valve and the seat/valve interface on both parts.... as well as decarbonizing the piston face.

I'm a new, to me, R56 owner... I'll be doing intake system cleaning with the BG 260 GDI intake cleaner before every 4000 mile oil change. I've had good luck with the BG products.

My new N18 R56 has just had the Walnut blast done it's nice and clean and was not really bad before... so, keeping it clean as possible with out another walnut blast is important to me... PLUS... this will help to clean the domes and seats of the valves that walnut blasting cant get to.
Talked to my local BMW/Audi guy who knows me well... and he's said that follow ups with the BG-260 have solved some issues that the walnut cleaning could not fully remedy... like lost compression from a small bit of carbon on the valve face that couldn't be removed with the walnut shells as the valves are closed for this service. HMM.

I'll also be doing this myself... I'll know that I can do a thorough job without paying someone that feels they're on the clock and cant take the time I can.

On top of that... I'll be using a top notch oil that has low NOACK (volatility) numbers to minimize on the cause of the deposits in the first place ...

The factory BMW/Mini LL-01 are horrible in this concern, no wonder the valves coke up!

I've always remembered the old ad from when I was a kid... "You can pay me know or pay me later"...
The N18 Seems to be a decent engine... and the deposits are no where near the problem that the N14's had... but I want to keep it that way for a while.

Seems to be plenty of atomizer kits for the BG liquids...at reasonable prices. I've had great results with the BG pro-grade chemicals... I believe they would function better to clean and keep clean our DI N14/N18 engines than the off the shelf 'spray cans'

Peace of mind for me.... and less hard work. Pricey oil changes... yep...I just hate downtime if I can avoid it, and take pride in my cars.

My 2¢











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Originally Posted by mountainhorse

Make sure you are using a good oil with low Volatility numbers and you probably will not have to revisit this operation. As, or MORE, important than that catch can.

MOST oils ... and especially the 0W oils have higher volatility which is more prone to Intake Valve Deposits.... (IVD's)

After the walnut shell blast... It's a good idea to also do a chemical clean... Like the

From a previous post of mine... Now, I'm switching to Redline oil... 5W-30.



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Originally Posted by Yupetc

I do a walnut blast every 10k miles (roughly 1-year) on both my R56's. Believe it or not, that carbon build-up does start to build and show some wet looking goo on the top side of the valves each year. (both my MCS are 2009's).

I'll also be designing a kit through solidworks or fusion-360 to machine a kit so I can insert a blow gun with different directions to blow walnut through the sparkplug hole and clean the top of the piston. Also a pipe to U-turn the walnut shells and clean the head dome room. For an old car if the piston gets cleaned up, it'll run smoothly like new again I got that outcome after I clean the piston from a head-gasket job, took all the weird noise and shakes out of the old car feel.