Rear Muffler

[Jon K]

I am not sure - the piston slap sounds more like the oil sprayer bar bolts are rattling around in the head. Apparently if you rev to 7000 you can vaporize the steel bolts and not have to pop the valve cover off.

[Incantation]

about 150k maybe..

that noise is something outside the engine.. the guy from whom i bought the bmw, a close family friend, also owner/operator of a bmw dealership with combined 100 years of experience in the shop said it's nothing to be concerned about

[Scott H]

just found it to be quite prominent as the rpms came down towards the end of the clip. I had the same on my 535 with 146k on it....just not as loud. It really was piston slap. We analyzed the crap out of it before and after taking my engine apart. The M30 block is big time durable and can handle it as there can be some slap in these engines as they age, but it's still nice to know what is going on. I'm just saying don't ignore it as it will help in case there IS an issue in the future....pay attention to it.

Oh...the guy I analyzed my motor with has a PhD from Northwestern and owns a data acquisition company in the motorsports field. Him and his father have a combined 60 years of experience building porsche and bmw engines as well as a client list with IRL, Champ, nascar, etc etc....basically anything with a motor and wheels/treads/propellers.

I was not ********ting about what I thought I heard....

about 150k maybe..

that noise is something outside the engine.. the guy from whom i bought the bmw, a close family friend, also owner/operator of a bmw dealership with combined 100 years of experience in the shop said it's nothing to be concerned about

[Martin in Bellevue]

about 150k maybe..

that noise is something outside the engine.. the guy from whom i bought the bmw, a close family friend, also owner/operator of a bmw dealership with combined 100 years of experience in the shop said it's nothing to be concerned about

Did the seller happen to know what the noise was? It seems to be a sound that could be indicative of problems in the motor.

You're really not interested in isolating the cause?

[Incantation]

that's interesting.. yea the noise is annoying but it comes from a pulley or something.. shrug. i would prefer it not be there but it's been around since i got the car at 89k and it only does it if i rev the engine in neutral which is basically never

[Incantation]

yea he did.. i can't recall what it was. i can't say i'm not interested in isolating the cause.. it's not something that is wrecking the system (apparently), and i never hear it because i never rev the motor.. so it's not really a priority. having said that if someone knows how to fix it i will do it.