Engine Diagnosing Help *Updated*

[sbay]

Hello fellow members,

Just purchased a 2002 M3 with “rod knock” as the diagnosis from the seller. Testing my luck to see if maybe the noise is the VANOS, or something else, before I go purchase a used engine/rebuild. Appreciate any advice or help!

Link to video:
https://youtube.com/shorts/L8THhM-rV...70AKr9zFPqrTrv

[BOOSTED]

Bad news Its rod knock.

[Arith2]

Hopefully you paid half price. That's a pretty knarly knock.

[sbay]

Was worth a shot lol, thank you as always!

[Arith2]

At least you bought a car worth fixing regardless. No matter what, after enough time you can most likely break even at a minimum

[sapote]

Hopefully the crank bearing journal is not badly damaged.

[Syfon]

Just pull the oil filter. If it's knocking, there will be metal in the oil. No need to keep running it. Time to tear it down and do a full rebuild. Can't just slap new bearings in and call it a day

[sbay]

I will update this thread down the line with pictures of the findings for anyone interested!

[Arith2]

I will update this thread down the line with pictures of the findings for anyone interested!

This is the kind of post that peaks my interest. I love a good mystery. Even after all the warranty bs and retarded politics at my dealership, it's this very thing that keeps the passion for working on BMWs. Good luck with it and hopefully it isn't too terrible to fix. Once you figure out what is wrong, it may be good to give Achilles Motorsports a call in Cali. The guy knows S54s very well and is worth talking to for some perspective at a minimum.

[ChapterM3]

sbay Definitely interested to see what findings you come of this - that is pretty damn bad rod knock! Wonder what it's going to look like once you pull it apart

[sbay]

Update: Took a while to get this job started…from saving, to ordering parts, to studying realoem diagrams and tis, to coordinating scheduling at my friends shop…but finally the engine is out of the car and I’m currently working on the rebuild. Decided on rebuilding it versus buying a used engine because what’s the fun in that. Attached are some pictures of the build and findings

Final verdict: Spun bearing and piston slap, and what looks like poor oil change intervals mixed with poor maintenance in general, original fuel filter at 86k miles, more oil gunk buildup than my previous 150k+ s54 as seen on the valvetrain…guess the poor man spec lives up to the name