Guess that noise - 2005 Mini Cooper S

[Won]

Recently acquired an R52S Convertible. I know I'm late to the Cooper S party (had an R56 before) but I can really see the appeal. Anyway, it developed this noise in the last couple of days. It's much more pronounced when warm. Any ideas? I will take it to a garage but thought you guys might enjoy a challenge. It has 83k miles. Unknown history on the clutch/DMF, which would be my first guess, and probably the most affordable one. There was already some noise in the clutch that went away with the foot down, but this one persists. Thanks!

[asphaltgambler]

The noise I hear that sounds odd is a low frequency rotational knocking sound. It seems that its concentrated on the flywheel side. Possibly a pressure plate finger that is failing and riding the T/O bearing eccentrically

Best bet if you have ramps or Jack stands is to get underneath with it running to locate the sound.
.

[Bob Kontak]

Originally Posted by asphaltgambler

Best bet if you have ramps or Jack stands is to get underneath with it running to locate the sound.
.

I like jack stands. Then you can put the car in gear and roll the wheels. Don't know if the Cooper S was AWD. Four jack stands then.

What ever the noise is it pulls down the engine RPM from the first vid.

[sc_rufctr]

No idea about the sound but be cautious. The front wheels will still turn if it's up on jack stands, running and in neutral.
Just the twist of the oil in the transmission is enough to rotate the wheels.

[astrochex]

The Cooper S engine from that era is not quiet by any measure. My car, for example is sensitive to oil level. It is noticeably smoother and quieter with the oil topped off than if it is even a little low on the dipstick. So I would make sure the oil level is good to rule out the valvetrain.

Hopefully, its not something like the waterpump, which is driven off the supercharger.

[colingreene]

I often use a long screwdriver to carefully prod places on the motor and put my ear against it.
This helps me locate noises fairly well.
good luck.
Also What up Astro!

[HardDrive]

Does the engine run smoothly above idle? Does it make any odd mechanical noises above idle?

[GothingNC]

Check the belt tensioner, is it bouncing around, the part that looks like a shock wears out around 30,000 miles.

Could also be the PTO gears in the Supercharger. You will know for sure when. It suddenly gets quiet and the temp gauge goes all the way to the left meaning the water pump is no longer being turned by the supercharger.

[GothingNC]

The last video is almost what mine sounded like when the PTO gears on the SC were going. I was able to get another 15,000 miles out of it before it really got loud and left me stranded on the side of the road. Car had 114,000 on it at the time.

Rebuilt units can be found at Way Motorworks.

https://www.waymotorworks.com/r53-r52-standard-rebuilt-supercharger.html

[VincentVega]

The SC scares me a bit. Almost half the value of the car in 1 (rebuilt) part. Good call on the oil level. I've tried a few different brands and additives. I swear I can hear a difference. Really!

I often use a long screwdriver to carefully prod places on the motor and put my ear against it.

x2

[rusnak]

Does that thing have a harmonic balancer? Has it been sitting for awhile?

[dewolf]

That sound is familiar. It's the DMF. Changed mine and all quiet.




Edit: You'll know if it's the balancer in a short time frame. It will start to pop and fart like crazy. Changed that sucker too.

[DavidI]

Get a mechanical stethoscope from your local auto parts store and try to isolate the noise. I am interested if the sound accelerates along with revving the engine. To me it sounds like valves.

[colingreene]

listening to this again its certainly the flywheel. mine did it forever its nothing to be concerned about.

[Won]

Thanks for the input guys. Sadly, I'm aware of the typical weak spots mentioned: the supercharger PTO and the disintegrating harmonic balancer. Hopefully I'll have time to address these in my own time. When the supercharger goes, I'll fit an electric water pump. The auxiliary belt side is completely quiet and there is no slop or bouncing belt. The phone does a decent job of isolating the noise source compared to my hearing. It's definitely coming from the transmission side, which doesn't rule out the PTO.

I'm leaning towards the source being the DMF since the noise is directly related to the drive. In the rolling video I'm just moving forward and backward. The metallic scratching noise on top of the rattle would fit the culprit being the clutch assembly.

All will be revealed soon!

Apart from this, I really like this car! The moment I got inside, I thought to myself "this is an old school car". Reminded me of the E36 and E46, probably because this Mini was also designed in the same era. In comparison, the R56 and E91 definitely already had the "newer" car feel. Doesn't surprise me that it's sensitive to the oil level, either. The build quality leaves much to be desired but I think that just adds to the character. I haven't owned any fun car since 2012 what with the 911 being stored on another continent, so I'm really enjoying this.

Question: The first time I've heard of DMF was in the context of 964/993, and the best practice seemed to be replacing it with a solid flywheel + sprung clutch. Most cars nowadays are equipped with a DMF. While there are solid flywheel conversion kits sold by OE companies like Valeo, some people report drivetrain failure which may or may not be related to the new flywheel/clutch behavior. Did it just work better in 911's because of the flat six? Are people using solid flywheel with unspring clutch disc? What's your opinion/experience?

[astrochex]

I’ve had a Valeo clutch on my MCS for over five years now with no issues.

Love the color of your car, Won.

[stealthn]

Which one of all the bad sounds are you talking about?

[billybek]

Originally Posted by stealthn

Which one of all the bad sounds are you talking about?

Lol. Maybe next time buy a petrol engine?

[maxnine11]

Did you record that in your laundry room?
It would be easier to diagnose the sound if you parked it further away from the out of balance washing machine and wore out clothes drier.

[Won]

What? I just used the standard YouTube guideline for recording random car noises. Try listening with some audiophile-grade headphones