[ryansbmw]

Hello,

I have 2013 X5 with a N55. Running MHD S2+ for the last 60k miles currently sitting at 176k miles. For the past year or so, Ive been getting this weird hiccup while moderately accelerating in higher gears between 1700-2500 rpm. Its almost like a hesitation sound. As the rpms climb, you can hear it quicken up and go away. By 2700 rpm, its gone and the car is accelerating smoothly. No codes. Have changed plugs ( NGK gapped to .022) and coils 2x with no change. Still need to do a log and see if that reveals anything. Mentioned it to my shop and they suggested walnut blasting.

Has anyone walnut blasted their N55 engines? And at what mileage? How bad was the build up? I know this is a much bigger issue for N54s and N55s dont have this problem but the posts I have come across were at much lower mileage. Theres no real way to scope the valves before without committing to the process which doesnt help my decision.

The X5 section can be a little dead at times so I figured I would post here instead.

[culto]

I had it done at around 120,000 miles. The car runs smoother after having it done. I’m glad that I did it.

[ChiltiCoatl89]

120k sounds about a good time to do it, early as 100k- or as late as 150k, some say as early as 80k, N55 are better about the valves compared to the N54s.

[ChiltiCoatl89]

Originally Posted by ryansbmw

Hello,

I have 2013 X5 with a N55. Running MHD S2+ for the last 60k miles currently sitting at 176k miles. For the past year or so, Ive been getting this weird hiccup while moderately accelerating in higher gears between 1700-2500 rpm. Its almost like a hesitation sound. As the rpms climb, you can hear it quicken up and go away. By 2700 rpm, its gone and the car is accelerating smoothly. No codes. Have changed plugs ( NGK gapped to .022) and coils 2x with no change. Still need to do a log and see if that reveals anything. Mentioned it to my shop and they suggested walnut blasting.

Has anyone walnut blasted their N55 engines? And at what mileage? How bad was the build up? I know this is a much bigger issue for N54s and N55s dont have this problem but the posts I have come across were at much lower mileage. Theres no real way to scope the valves before without committing to the process which doesnt help my decision.

The X5 section can be a little dead at times so I figured I would post here instead.

You're definately due for a nice Blastin'.

[ChiltiCoatl89]

For Reference, here is a DIY Kit from FCP, Most of us 5er Owners use ECS, and mainly FCP Euro, and we highly recommend FCP if you haven't already due to their lifetime warranties. (ECS has it as well to some extent) There is also a basic Kit without a Valve cover and its Definately less expensive. Plenty of Videos and even a video from FCP Euro on how to Walnut blast our N55s.

[ryansbmw]

Originally Posted by ChiltiCoatl89

For Reference, here is a DIY Kit from FCP, Most of us 5er Owners use ECS, and mainly FCP Euro, and we highly recommend FCP if you haven't already due to their lifetime warranties. (ECS has it as well to some extent) There is also a basic Kit without a Valve cover and its Definately less expensive. Plenty of Videos and even a video from FCP Euro on how to Walnut blast our N55s.

Thanks for info! I love FCP and have been using them for the last 10+ years on my E39, E70 and E60. I just had my valve cover replaced last fall so I will check out the other kit and videos. I would probably leave this for the professionals to do. I like to think of myself as handy but I just dont have good luck when it comes to the more involved work on my cars. Something always goes wrong....and with a wife due with our 2nd any day now, breaking my car is not something I want to add to the stress list hahah.

[Surly73]

This is on my list for this spring/summer

[B-Buster]

Did mine at +/-85k, made quite the difference.

After that I had a little hiccup, hardly noticable and only at low RPM. A smoke test showed that one of the clamps of the pipes after the MAF had to be replaced, it allowed for a very small airleak. Engine ran smooth again once that was taken care of.

[ChiltiCoatl89]

Originally Posted by Surly73

This is on my list for this spring/summer

FCP Euro and the video they made makes it look easy, just wondering how easy it will be, I am pretty excited, I've used the CRC Intake valve cleaner however I don't want to clog up my Catalytic Converter at all, If it really did help because I didn't inspect the intake after i did the procedure, so I believe the Walnut Blast will do me good for another 80k or so.

[Surly73]

Originally Posted by ChiltiCoatl89

FCP Euro and the video they made makes it look easy, just wondering how easy it will be, I am pretty excited, I've used the CRC Intake valve cleaner however I don't want to clog up my Catalytic Converter at all, If it really did help because I didn't inspect the intake after i did the procedure, so I believe the Walnut Blast will do me good for another 80k or so.

I find usually nothing is as easy as it looks. Especially on cars that aren't constantly taken apart for mods or tinkering and have age (oh, gee, like mine). Pulling the IM with all of the connectors, clips, the DME and all of its harnesses, surrounded by hardening rubber hoses etc... doesn't sound like my idea of fun, but neither does paying someone else to do it. So...

During my OFHG job where I moved the IM to the side I took a look at my valves and they looked pretty good. However I've had rough idles, some cold weather cold start stalling, and some other things for YEARS I would love to cure. I was under warranty when it started and I got all new plugs and injectors under warranty - still there. ISTA says the VANOS and Valvetronic pass all tests. ISTA's rough running functions show slight deviations moving around all cylinders, no one is to blame. I replaced coils and plugs again - better, but still there. Smoke tested intake - no issues.

So now we're trying walnut blasting. Something I should probably do anyways as PM. It might also be the purge valve...hmmm

[ChiltiCoatl89]

Go the most meaningful and cost-effective routes first to clear your mind of possible issues. Some of the best ways to save money and pinpoint an issue.

[culto]

I would be careful about doing it yourself if you don’t have the proper expertise. I saw a tear down video of an N55 engine and the mechanic doing the tear down thought that the engine was toast because the person doing a walnut blast didn’t know what he was doing.

[ChiltiCoatl89]

Originally Posted by culto

I would be careful about doing it yourself if you don’t have the proper expertise. I saw a tear down video of an N55 engine and the mechanic doing the tear down thought that the engine was toast because the person doing a walnut blast didn’t know what he was doing.

Yeah that procedure is one for people who have more experience in cars, not saying people who don't have a know-how on cars cannot do it, however, its tedious, and would be easy to miss something or not block something and make a mistake.