Anyone know how to tell if a dual-mass flywheel needs replacing? I have to do the clutch and throw-out bearing on our 2002 MCS with only 56K miles, and don't want to spend the $$$ on a new flywheel if possible.

I put in a UUC lightweight flywheel and sprung-hub clutch, but the tranny rattle is unbearable. Have to go back to something closer to stock for our daily-driver, even if it means putting back in the dreaded dual-mass flywheel
Thanks,
Ian

 

If you grab the toothed part of the flywheel with one hand and palm the surface with the other, and you twist. If it has a lot of play, I would suggest replacing it. I would also inspect the surface, if it's scored or cracked, I would also have it machined, or replaced. If you want to get an OEM dual mass, make sure you get the part 21 20 7 548 804, as this is the part related to the bulletin.

 

Thanks for the suggestion. I made a fixture that I could bolt to the hub of the flywheel without interfering with the outer disc. I can rotate the flywheel and it will spring back, suggesting that the "shock absorber" function is working. I grabbed it like a wheel and tried to rock it to test for radial play, and did not find any other than a slight flex from the rubber core. Based on this exhaustive analysis, I suspect the flywheel is still good. The flywheel only has 56,000 miles on it, anyone know what kind of lifetimes have been seen for dual-mass flywheels? If this was a solid flywheel I wouldn't be concerned at this mileage.

What bulletin are you referring to? Was there a replacement for the early (7/2002) flywheels?
Ian

 

When I called my dealer for the flywheel, they wanted to sell me #21 20 7 532 057 instead of the updated #21 20 7 548 804. I'm confused, does the updated flywheel not apply to my MCS from 7/2003?
Thanks,
Ian

 

No, it applies to all versions of the MCS. The update was due to the fact that the flywheels would glaze over create all sorts of weird noises. How far were you able to rotate it? Given that it has to transmit all of the torque from the engine I would have expect it to be impossible to rotate like you did.

 

The bulletin I am referring to is one of the flywheel rattling at idle, the updated part is supposed to be a bit stronger and absorb more of the rattle than the standard.

 

I was finally able to get the updated 804 flywheel, but I had to call two dealer parts departments before I could get a straight answer. The 057 part is what comes up as default when they look up your car (just like realoem). There is no notice in the system of an alternative part. However, if you give them the part # they will find it as a legit number. The first place I tried denied any knowledge at first, then they said they only sold it to customers who came in with the rattling complaint. The second place found the 804 number, had both in stock and offered me my choice. Plus, the 804 is $200 cheaper than the 057.

Thanks for all the good information, I wouldn't have known about the alternate part, or if it was appropriate for my car without this group
Ian

 

Having had both flywheels, I would do things differently in retrospect and keep the OE flywheel and clutch disc. I had the rattle with the OE flywheel; there was some slipping at high rpm gear change, and pedal effort was high with narrow engagement, although the clutch disc looked great at 70k miles. With the 804 flywheel, new disc, and pressure plate, came the Chewbacca howl. Although I have not had the howl in a long time, I would have gladly kept the OE's rattle over the 804’s howl. The rattle could have been reduced by updating the guide tube and clutch release bearing (which I did after getting the howl), plus going 50/50 with a higher viscosity gear box lube. New brake fluid, clutch slave bleed, and pressure plate would have fixed pedal effort and engagement. Sometimes you don’t know how good you had it until you get something worse.

If you did not change the guide tube or clutch release bearing, get the recent versions before dropping the transmission. I have photos of the differences between parts but the gallery server is down for a few days. Before giving up on the UUC, try the lube blend; drain the gearbox and put a quart of MTF-94 or Redline MTL, top off with either Silkolene SYN 5 or Redline MT 90.

 

Ah well, I guess nothing's ever perfect. The UUC recommended mix of 50/50 Redline 75W140NS/D4-ATF did quiet some of the rattle down, but it was still too much for my wife pretty. UUC then suggested 50/50 Redline 75W140NS/MT-90, which did a remarkable job of quieting the tranny rattle. However, it gets pretty cold here in Rochester in the winter, and I'm not comfortable with that thick a tranny fluid when temps get below 15 degrees.

So it's back to the oem flywheel and clutch for us. If anyone wants a good price on a UUC aluminum flywheel and sprung clutch...

Ian

 

The 804 is also the updated part for the howling BTW. If the howling occurs, it should be covered under a parts warranty, but I think parts warranty would only be granted if the work was performed at the dealer.

 

That's good to know. With hindsight, I realize I've had the tranny rattle for over a year. Never having owned a FWD car before, I thought the rattling coming from my engine bay was rod-knock or something else from the bottom end. Now I can tell that it was the tranny. I was also getting the screech when letting out the clutch from a stand-still for the first couple of starts each day. The dealer could never hear it and ignored my complaints under warranty, and I assumed it was a belt problem. The car is out of warranty now and I replaced the belt to no avail; perhaps now with a new clutch & updated flywheel I'll have a Mini with no rattles or screeches.
Ian

 

Read post #8 again, the 804 is a howler.


And yes, at least at our local dealership, it must be MINI service department installed, diagnosed, and replaced, to be covered under warranty.