I have a 2005 R53 with 60k miles, the only mods are a cone air filter and milltek sport exhaust. Upon startup it has a very definitive whine sound similar to the whine from sport bikes. I have ordered a replacement belt but I’m not sure that is the cause. I am starting to think it may be a vacuum leak somewhere in the system but I have not found any thus far. Also I’ve noticed a tapping sound coming from the hot side intercollegiate horn. I included a couple audio files to help identify the issues. Hopefully I am just overreacting but I don’t recall this whine sound in my 06 that I had. Thanks!

 

Sounds like it could be one or both of the idlers. This is a common issue around this mileage. #1 is 11288620210, #3 is part numbers 11288625983. These are easy to check and cheap to replace, just pull the belt and feel them for grinding or play.

 

Is the cone air filter drawing cold air, or is it open to the engine compartment. If so, it is not getting colder denser air. The whine be a leak in the intercooler gaskets, or the green seal, that connects the supercharger to the intake horn. Leaks there are common. If it is the green gasket, you will need to put the front end into service mode, to work on it.
Also check the pcv on the passenger side of the engine, just behind the intake horn.

 

Thanks for the info. I attached a pic of the intake setup...how could I ensure cold air is being drawn in?

As as far as the green seals, I’ll have to do some research on those as I’m not too familiar with them. I have read in some posts about them but nothing further. Are these the seals connecting at the top of the intake horn, or is it on the bottom side?

I have a new pcv on the way and will be replacing that when it arrives.

 

I appreciate the info! I’ll add these to my order and replace them with the belt when it arrives. Hopefully it will cure the whine and rev issues I’ve been having.

Is is there a way to check these without pulling the belt?

Thanks!

 

If you are checking for vacuum leaks, make sure you also give your intercooler boots a good look. Mine didn't seem cracked on the top, but on the bottoms and sides they were completely rotted away.

 

On the JCW models the cowl just behind the end of your air filter is cut out. The air is drawn from the cowl, which is much cooler than the engine bay temps. You would then need to create a lid for the top of your air filter housing, You could glue a piece of plastic(maybe clear) to the rubber rim pieces. That way you can see the air filter and it may look cool too! It will also keep out the hot engine bay heat!

 

I think you'd have to pull it. If you have the tensioning tool it's a pretty simple procedure - then you can feel these through the passenger wheel arch.

Alternatively, one of the best ways I've found to isolate sounds is a few feet of fuel hose. Stick one end in your ear and move the other end around the engine bay. Bam, improvised stethoscope!