Help diagnose noise coming from a 2011 MINI Cooper S

My wife's MINI started making a noise recently that sounds like a cross between an air raid siren and a jet engine idling.  It occurs within a minute or two of startup in bursts (2 to 4 times), then goes away.  This happens whether the car is being driven or sitting and idling, so I'm fairly certain it's the engine.  I'll ask her to shut it down to confirm.  If the throttle is raised, the noise lessens but doesn't go away.  Anyone want to venture a guess?  I'm thinking turbo.  Water pumps can be problematic on these cars, but I've never heard a water pump make a high screech like this.

BTW, the car only has 75k miles on it.  Oil has been changed on roughly half the recommend service interval.  Thanks in advance for thoughts and commiseration.

I would need to do some additional digging, but I recall the timing chain tensioner on R56 engines is known for being problematic. I heard they fixed it with an engine update during hte R56 production, but I don't recall the exact year that was implemented. 

 Air raid sounds to me like a vac/air leak, or a supercharger. No one spontaneously supercharged it, did they? 

Based on what you're saying , id giess closer to the turbo. Noise lessening under accel would tell me that the system pressurized makes it better.

From what I've read, timing chain issues present as more of a rattle on cold startup (the Death Rattle).  Maybe the chain is getting badly displaced and contacting metal.

In reply to JoeTR6 :

Possibly. Has she said if it's down on power/tough to accel? My ms3 made what could be described as a similar noise right before it decided to sneeze snail guts.

It usually happens leaving work, and they have a very large parking lot with slow speed limits.  So she probably isn't really on it while it's occurring.  There's no loss of power when I've driven it.  It still feels pretty snappy.

I would doubt its timing chain as the noise as different as you stated.  My guess is that it is certainly rotational and as it warms expands and lessens the noise.  It could be bearings in the turbo.  My water pump went out once but it also did not sound like that.  I think more likely is an idler pulley may be an issue.  They're a bit buried at the front of the engine.  I replaced mine when I had a coil pack go out last year and one was just starting to fail.  That was at around 50k miles

Could it be the vacuum pump? Has your wife noticed any issues with a hard brake pedal? 

My first guess was going to be a secondary air pump, but the R56 doesn't have one according to the internets. 

thewheelman said:

Could it be the vacuum pump? Has your wife noticed any issues with a hard brake pedal? 

My first guess was going to be a secondary air pump, but the R56 doesn't have one according to the internets. 

The brakes feel fine.

Unfortunately, the problem almost never occurs when driving from the house.  This has me puzzled because it has been warmer recently outside when the problem occurred than it has been in our garage typically.  So it doesn't seem to be so much outside temperature dependent.  I'm out of town next week, so we may just have to drop it off at a shop for diagnosis.

PCV plugged up ?

This morning, with my wife driving, we went on a short drive to reproduce the noise.  It's been getting slowly worse, so it started a few hundred yards from the house.  We pulled over and I got the hood open with it still happening.  Didn't sound like the turbo, but was coming from the passenger side of the engine towards the back.  I also caught a faint whiff of coolant, and the thermostat housing is fairly new.  So most likely a water pump crapping out.  That will be three in 75k miles.  WTF, MINI?

May as well refresh the belts and idler pulley while in there.

Thanks for all of the suggestions.

Does the car have an air injection pump?  If that's flaking out, might explain why it happens on startup - I think those run on cold start.

Also, does it have one of those cyclonic oil separators like BMW's?  When mine went bad it made kind of a honking sound intermittently.

Not sure how similar the engine systems are to BMW's.

Honestly, I'm not certain what this car has as you can't see much and I don't have a shop manual for it.  The sound is more like freight train brakes.  It's a metallic whine/whirring that sounds an awful lot like a bearing packing it in to me.  The car is getting dropped off tomorrow for checking and I'm ready to say good riddance.

Ouch.  Unfortunately, the R56 is definitely getting a reputation for being a needy beast as they age.  Oddly enough, the F56 is apparently a considerably better car - to the point where dealers are suffering due to the drop in warranty work compared to the R56 and R50/53 before it.

I just wish the F56 wasn't so damn ugly...  

Ian F said:

Ouch.  Unfortunately, the R56 is definitely getting a reputation for being a needy beast as they age.  Oddly enough, the F56 is apparently a considerably better car - to the point where dealers are suffering due to the drop in warranty work compared to the R56 and R50/53 before it.

I just wish the F56 wasn't so damn ugly...  

I'm starting to like them, especially the clubman. I may look for one in the mac and cheese yellow they have. 

In reply to Mndsm :

True... the Clubman doesn't look too bad.  The extra overall length evens out the extended nose.

Ian F said:

Ouch.  Unfortunately, the R56 is definitely getting a reputation for being a needy beast as they age.  Oddly enough, the F56 is apparently a considerably better car - to the point where dealers are suffering due to the drop in warranty work compared to the R56 and R50/53 before it.

I just wish the F56 wasn't so damn ugly...  

Agreed.  I had a F56 Clubman loaner last year, and it was (to me) too soft and heavy feeling.  But it was a very nice car to drive.  I cringed every time I saw it, though.

My wife has talked about trading in her R56, but doesn't like the new ones and can't find another car that is as fun to drive.