[sfgeese]

Hi folks,

I kept a 2014 BMW 328i (sulev engine) for about 4 years as 2nd owner (drive it from 85K to 160K mi), bought it from a non-BMW big dealer, but never recognized and knew the existence of the suddenly-coming spark-plug problem --- Most recently I found the car suddenly shook while driving and there was big noise from engine as well as exaust pipes, but still drivable (slowly at only 20+ mph) with an error msg "drivetrain malfunction".

Then a technician found 3 of 4 spark plugs have had cross-threading issue and stucked. COULD THIS BE FIXED? I still hope to keep the car since already having spent several grands to maintain it well as I can (despite minor issues, it has been a working horse daily!). THANK YOU A LOT, many great users here, for your suggestions and advice! ---Andrew

[Billfitz]

The head might be able to be tapped to use a larger plug.

[sfgeese]

Thanks a lot Bill! I will mention this helpful thought/suggestion to the technicians who may want to help.

[wishbone]

This thread should be merged with the ones where people are asking if they should use the tubing to slowly feel the spark plug get threaded

[B58 parts]

Three out of four wow. Who was working on that car. It would probably be easier just to swap a used cylinder head on. For that motor you could probably find a used cylinder head for a few hundred bucks. I'm not sure why this happens so often. Of all things to be careful with. Go left a little before you go right and they seat right in.

[Billfitz]

Whether swapped or tapped the head would have to come off anyway, so for me the deciding factor would be which is less expensive, having a machine shop tap the existing head or putting on a used one.
How it happened is simple, some idiot forced the plugs in with a wrench without first screwing them in with hand pressure only.

[Dr_Bob]

Hi. This has been covered elsewhere on the forum:
https://f30.bimmerpost.com/forums/sh....php?t=1993508

If the thread can't be re-tapped, then you can get the shop to put a helicoil insert into the plug hole (those may have a different name across the pond). I've had these on a few old motorcycle plug holes and a couple of sump plugs and they last.

I'm not sure there's enough space in the head to tap for a larger diameter plug - if one is available with the correct heat range and length.

[sfgeese]

Thank you for the informative notes.

Originally Posted by Dr_Bob

Hi. This has been covered elsewhere on the forum:
https://f30.bimmerpost.com/forums/sh....php?t=1993508

If the thread can't be re-tapped, then you can get the shop to put a helicoil insert into the plug hole (those may have a different name across the pond). I've had these on a few old motorcycle plug holes and a couple of sump plugs and they last.

I'm not sure there's enough space in the head to tap for a larger diameter plug - if one is available with the correct heat range and length.

[sfgeese]

Thanks, right it must be due to the prior owner and related work.

Originally Posted by Billfitz

Whether swapped or tapped the head would have to come off anyway, so for me the deciding factor would be which is less expensive, having a machine shop tap the existing head or putting on a used one.
How it happened is simple, some idiot forced the plugs in with a wrench without first screwing them in with hand pressure only.

[sfgeese]

Thanks for the note.

Originally Posted by wishbone

This thread should be merged with the ones where people are asking if they should use the tubing to slowly feel the spark plug get threaded