E92 m3 engine knock, any ideas?

[vmudry]

Hi everyone, I have a 08 bmw m3. After taking the car for high speeds, I started to hear engine knock coming from top of the engine. It almost sounds like a Diesel engine. While driving the car the knock appears at around 1800-2500 rpm in first 2 gears and 3rd gear and up its harder to hear. Next day I changed the oil and the filter and slowly drove it around the neighborhood. But the knock is still there... Few days later I started the car in the cold and heard few various knocks in the engine and it went away. Engine works perfectly tried raising RPMs still everything was fine. Once the car got warmer I start to hear knocking at about 2000rpms. Once it got to normal temperature it knocks anywhere from 1500-2500. The more RPMs I give it, the more knock I hear. The car has around 56k miles on it. Any ideas what that could be? Thank you

[SunnyD]

My first guess would be bad gas, but I've read too many threads on rod bearing issues, so I hope it's not that.

[vmudry]

I always put 93 in it. And I drove like half tank out, everything was fine. Then I got it going 180mph. After I slowed down, I heard knocking noise while shifting gears

[SenorFunkyPants]

A knocking noise that is louder at ~2000-2500 rpm is indicative of high rod bearing wear/imminent failure.
Posting an audio clip of the noise might help to diagnose.

[tony093]

It is possibly a broken valve spring

[kb9uwu]

ROD BEARINGS!!!!!! ok not really, carry on

[///M Power-Belgium]

Originally Posted by SenorFunkyPants

A knocking noise that is louder at ~2000-2500 rpm is indicative of high rod bearing wear/imminent failure.
Posting an audio clip of the noise might help to diagnose.

+1 !
Try to post a Video clip and stop "ASAP" with driving your car if you don't want a black hole in your engine block !

[Time Lord]

Rod bearing

[quicktwinturbo]

Is it typical to hear some ticking? noise at low rpm?

[Wilsel]

How many miles are on it? Does the noise sound like it's coming from the top (valvetrain), or from the bottom (rod bearings). Also what RPM were you running at 180 mph?

[///M Power-Belgium]

Originally Posted by Wilsel

How many miles are on it? Does the noise sound like it's coming from the top (valvetrain), or from the bottom (rod bearings). Also what RPM were you running at 180 mph?

Read again the OP post => He has 56K on it .

[vmudry]

And I don't drive the car anymore

[vmudry]

Originally Posted by Wilsel

How many miles are on it? Does the noise sound like it's coming from the top (valvetrain), or from the bottom (rod bearings). Also what RPM were you running at 180 mph?

I think it was around 6-7rpm at 180 not exactly sure but going 170mph it was at 8100 going in 5th gear

[vmudry]

I hear the noise from top of the engine, but it's really hard to tell.. M3s are really noisy cars plus I have a aftermarket exhaust on it

[vmudry]

Checked the old filter.... Might know what the problem is now.... :

[Killerfish2012]

Originally Posted by vmudry

Checked the old filter.... Might know what the problem is now.... :

em....any ideas?

[vmudry]

Oil filter is covered with fakes..so pretty sure it's rod bearings

[modkrazy]

Originally Posted by vmudry

Checked the old filter.... Might know what the problem is now.... :

Ouch, that's not a good sign, that's a lot of shiny shiny.

[Doctor J]

That's an expensive sound

What the heck are you driving at 180 mph for? You suicidal?

[tinman831]

Yup. Don't drive that car anymore. Time to crack that engine open and take a peek inside.

[m3power13]

Another one bites the dust.....

[SenorFunkyPants]

Originally Posted by vmudry

And I don't drive the car anymore

Yeah sadly a knock that becomes louder as you approach 2000 rpm is quite typical in cars with imminent crankshaft bearing failure...sounds more like main bearings but given the S65s history it could also be a rod bearing. You will very lucky if your crank is reusable.