Folks,
Problem with my 2009 R55 Non-S, N12 engine.
I have a strange noise from my engine bay, what I would immediately say is a hydraulic pump with air in it or damage. But, my car is a manual trans with electric power steering - no hydraulic pumps to my knowledge.
Loudest on initial start, quickly dies down within 1 second of starting - probably related to oil pressure. I've seen something about a tensioner for the water pump??? That's something I've never experienced before.
Has anyone had any similar experience that might point me in the right direction of finding the root cause? It's difficult to tell where it's coming from, other than the accessory drive area.
Thanks in advance!

 

One trick I've used with other cars to first confirm a noise is either coming from the accessory drive or the engine is to remove the accessory drive belt and cold start the engine and let it run only long enough to confirm the noise is absent or still present. My experience is with the belt removed the noise was not present.

While I had the belt off I checked all accessory drives for excessive bearing play. My experience is the one accessory drive that had play didn't have lots but compared to the other drives which pretty much had none that was significant.

A visual check found signs of coolant leaking from the water pump seal.

Also, with a serpentine belt one edge -- the inside edge -- was sharp. A quick check of the old belt -- which I just happened to have laying around -- found even after 60K miles of service the edges were dull. The new belt was sharp because of the bearing play it was not tracking true and the edge of the belt was rubbing on a pulley.

While you are there you check any idler/tensioner roller bearings for rough feeling, excessive play, and the rollers for signs the belt may be slipping on the idler roller.

With one car I found a water pump accounting for the noise. Another car an idler roller bearing that just happened to be real close to the power steering pump. With this car I had the bad idler roller bearing replaced, along with the other one and the tensioner. Some more than a few thousand miles and several years later I heard a faint chirp on cold start. Another bad idler roller bearing. Again I had both replaced along with the tensioner. Put lots more miles on the car and no more accessory drive issues. Well, until the water pump went bad.

Oh this car manifested a high pitched noise upon rolling to a stop. Long story short it proved to be a bad pressure relief valve in the power steering pump. The valve was not serviceable so I had to have the power steering pump/with an integral power steering fluid tank (which had the pressure relief valve) replaced with a new one.

None of my experience is with any tensioner (inside or outside the engine) that relies on oil pressure.

 

I also have the same noise, just about bang on for a worn power steering pump. Did you get your noise sorted?