A good friend of mine with average weekend car guy mechanical knowledge has a 2011 F10 N20 he bought CPO’d about 5 years ago or so with fairly low mileage. Shortly after he got it, somehow a drivetrain malfunction light turned into needing an entire motor gratis BMW. I forget the exact circumstances, but it wasn’t a catastrophic failure - it was a rabbit hole the dealer went down & ended up replacing the entire engine under warranty, and possibly the transmission as well if I recall correctly. Car was at the dealer forever.

Fast forward a few years & warranty is expired. He was driving along one day & “drive train malfunction” light comes on & car looses power. Car gets shut off & sits - turns it back on & all is fine. Same thing happens intermittently, seems worse when weather is hot. It could go a week without happening. Friend takes it to trusted BMW indie shop. They tell him it needs “complete turbo” at a cost of like $5-6k.

That’s a lot of money. Friend then takes car to good BMW dealer in area & they tell him same thing basically with a higher estimate. To me, former American car flat rate dealership tech (1990s) - something sounds odd… This intermittent issue replays over and over with the car. If the turbo impeller was broken, it wouldn’t be intermittent. If the bearings were bad, it would be loud or seized by now.

So, one day I have a few mins & throw my Foxwell 520 BMW scanner on it. Scanner works perfectly with my e85 M, but for whatever reason is unable to communicate with this car. Scanner says it’s compatible with 1997 & newer BMW & has a good reputation. Seems odd. Try scanner again on my car & works fine. I did not have time to visually inspect under the hood at the time.

At this point - I’m wondering if anyone has had a similar issue. I did some internet googling - but, other than the rusty waste gate cotter pin or noisy turbo, these don’t seem to fail a lot. A saw a few took it to dealer & they replaced turbo under warranty posts, but no real specifics of what was wrong with the whole massive turbo assembly, which seems to be waste gate, manifold, turbo, some gaskets, bolts, etc…

This is an intermittent problem going on for 9 mos. seems like it turbo blower itself was “bad” it would not be intermittent & would have grenaded by now. I know about turbos, but back in my day they were pretty uncommon, so I don’t have a ton of experience with them.

I’m wondering if anyone has any insight on exactly what part of the turbo assembly may be bad? It seems to me it would more likely by an issue with waste gate or DME software. Also, any idea why scanner won’t connect? It seems dealer / indie was able to retrieve data..

These are the facts as I know them. I know all info isn’t here & im working on visually inspecting turbo & emailing Foxwell. I feel like just replace everything and it will fix it means they may not even be sure exactly what is wrong or if it will even fix the problem. We know how that goes, spend $6k & they find something else is the problem… Then all of a sudden it becomes you need THAT to fix the original problem, plus “yeah you needed a turbo, too”.