Well I crossed over to what I call THE DARK SIDE. I came across a 09' R57 Manual trans with the N12 and owner reports misfire after driving 30 or so minutes. I ran codes an indeed found a code for #3 misfire. I also noticed a whine sounding exactly like a power steering pump running low on fluid. The whine increases with RPM. I decided to do an oil change and after draining the oil thought I would check the pump for any debris in the pickup potentially blocking the flow. I found it to be clean and thankfully no chunks of guide in the pan. Car starts no rattle and no whine until you give it some RPM. My question, aside from the misfire (I will get into in another thread) anyone have an issue with an oil pump sounding like a power steering pump? Im thinking about ordering a pump but they are relatively expensive so thought I would ask. And yes I did check all the rollers and replaced a very cracked belt. I did run a search but of course no one reports back.. Im sure the noise isn't normal as I would think they wouldn't be selling very many Coopers that sound like they are supercharged but aren't. Thanks in advance for any experienced direction.

 

Oil pump whine is not likely. The pump gears operated submerged/surrounded by oil. This oil tends to support the gears and they do not make contact with even the oil pump housing. The gear teeth are involute which means they roll against each other they do not wipe/rub against each other.

I'd be very surprised if what you are hearing is really/truly oil pump whine. However, any pump suspected of making noise needs to be removed and checked for wear/signs of trouble. And if in doubt replaced. While the pump is rather expensive if it fails you'll be buying a new pump along with a new engine. You think the pump is expensive...

But before you tear into the engine think you need a higher confidence diagnosis of where the noise is coming from. Far and away engine noise "engine whine" is from the accessory drive system. Most often a water pump proves to be the source of the noise. But it can be an idler roller bearing, a tensioner roller bearing.

I would recommend you obtain a mechanic's stethoscope and use it to pinpoint the source of the noise, or at least determine it is or is *not* coming from the area of the oil pump.

 

Yes did cover those bases and ultimately ran it without the belt. I just ordered the pump and chain last night. One thing I did notice when removing the original pump to see if there was anything obvious, the drive chain seemed very loose. Thinking I may replace the chain and give that a go before replacing the pump. At least it’s very easy on these to drop the pan. Thanks for your input.