[Alex323Ci]

it could be a cracked rear axle carrier panel (RACP) which is often improperly referred to as “subframe”.
it could also be a number of things like a broken dead coil in a rear spring or even broken rear shock mount. you’ll need to get under and examine.

BMW didn’t do the epoxy foam from the facotry. it was a later fix for some smaller cracks during the voluntary recall inspection around 2009-2010. so yes, if your car had small cracks and was inspected then BMW could have done the epoxy foam.

 

[Alex323Ci]

hasn't paid attention to this problem...for my 325
would any M54 3.0 susceptible to this?

yes. earlier pre 2/2000 builds the most.

 

[Alex323Ci]

Subframe is out! Mounts are not cracked, should I epoxy them for the faster turn around or weld them anyway

hard to say. there’s three ways I see of approaching this and all three fit a different want/need…
1) do nothing. car likely lasts it’s user “lifetime” never needing it. save time/money but never being positive it’s not going to be an issue later.
2) epoxy foam. some peace of mind, not a lot of work/money. but not knowing if crack in front right might happen or rust breach.
3) plates. peace of mind all four mounts are reinforced. also helps alleviate internal rust breach at mounting locations. more overkill, more money/time to have done. raises rear. will also need an alignment.

 

[Alex323Ci]

Invariable one of the first questions from a buyer will be the condition of the rear subframe followed by rod bearings, oil pump nut.

he doesn’t have an M3

 

[Alex323Ci]

If you had a 1998/1999 e46 you have a chance of cracks starting.. In rare case’s.

I wouldn’t say it was “rare” in those cases at all.

 

[Alex323Ci]

I disagree. There was a massive subframe thread on this forum back in early 2010 with tons of 325/330 with subframe issues.

i’m extremely familiar with that thread. it’s almost all 323/328.
(not saying it doesn’t happen to 325/330s but that thread isn’t a good reference for your point.)

 

[Alex323Ci]

If you could find the thread again, I'd be curious to take a look. According to analysis from CMP, ALL E46s are subscetible to this, the engine size doesn't really make a difference except more power=cracks come sooner

again i’m not saying it can’t happen to 325/330s. i’ve been saying this for well over a decade before the guy at CMP got his first E46. it’s just nowhere near as common as 323/328/M3s