[Ushan86]

Hey guys,

I've got this knocking noise in the engine and I was wondering if anyone has ever experienced that. Sounds like someone knocking the engine block with a hammer. It appears only between 2000 - 3000 rpm and only if I floor the throttle. The engine doesnt make that noise during regular driving. Any ideas before I take my 328i to dealership and they rip me off?

Many thanks

[leebermeister]

Do you have an N51 or N52 with the 3 stage manifold mod?

[Ushan86]

Originally Posted by leebermeister

Do you have an N51 or N52 with the 3 stage manifold mod?

I will find that out tomorrow. But it looks like I have the same problem as the guy on this video:

http://youtu.be/QUckZ6vpPIE

And it looks like its pretty expensive to fix this problem. Can I just keep driving with this (is it just a "cosmetic" issue)? Or is it a major problem that will blow up the engine at some point?

Thanks

[Ushan86]

Originally Posted by leebermeister

Do you have an N51 or N52 with the 3 stage manifold mod?

Okay, found it:

N51, not sure about 3 stage manifold though.

[Johnny D]

Is it a tick or a knock? Can you record it?

If it's a constant tick it could be as simple as lifter noise which isnt a problem and common on these engines.
If it is a knock you're possibly looking at a spun rod bearing and a large mechanic bill.

[Ushan86]

Originally Posted by Johnny D

Is it a tick or a knock? Can you record it?

If it's a constant tick it could be as simple as lifter noise which isnt a problem and common on these engines.
If it is a knock you're possibly looking at a spun rod bearing and a large mechanic bill.

Ill record it tomorrow. But for now ive found the following video and it sounds like this:

http://youtu.be/Yasgo4BCKT0

[Ushan86]

Gents, also any recommendations on how to check if it is a spun rod bearing problem?

[leebermeister]

Your N51 should have a 3 stage intake manifold. Have your DISA in your manifold checked to see if the flaps or any associated parts are loose causing the sound. When you said the sound comes during heavy accel between 2 - 3,000 rpm makes me suspect it.

[Ushan86]

Originally Posted by leebermeister

Your N51 should have a 3 stage intake manifold. Have your DISA in your manifold checked to see if the flaps or any associated parts are loose causing the sound. When you said the sound comes during heavy accel between 2 - 3,000 rpm makes me suspect it.

I hope you are right, man. Again it does not occur during normal driving, only when I floor the pedal. The knocking goes away after 3000rpm. I checked oil and it is at optimum level (3 bars) as it was when I got an oil change 3000 miles ago.
Can anybody recommend a good mechanic in Philadelphia, Southern Jersey area who can take a look at my car?

Thanks