GL320 Main drive pulley coming apart
 

Doing a routine visual inspection, and I notice that the main drive pulley on the end of the crankshaft seems to be losing some kind of rubber insert. I looked up the drive pully part number (6420300003), and it doesn't look like the rubber insert is a separate part. Have any of you seen this? Is the solution to replace the pulley?

https://cimg7.ibsrv.net/gimg/www.mbw...2ad725f983.jpg

Main drive pulley losing rubber insert

Yes, replace. Personally, I would not drive the car with it like that as internal damage could be done. That is a vibration dampner pulley (like most, if not all, cars). The rubber absorbs vibration between the crankshaft and the rest of the engine. With the rubber sticking out like that, it's most likely also out of balance.

dont drive. it will come apart, shrapnel and cause _a_lot_ of damage...

Thanks for the replies. Well, I have set foot to the path of replacing the harmonic balancer. Checked to see if this part (with only 60k miles on it) has a recall or TSB associated with it, but no luck, despite its failure looking exactly like a similar failure a few years earlier with other models' harmonic balancers (which had a TSB). Started hunting for the correct part, and discovered that it has been upgraded/replaced twice, and that the latest generation is part #6420300503. You can get the "old" model pulleys for about $200 brand new, but to get the latest, the prices started at $500 for OEM parts online. Dealership retail was close to $800!! Worse still, nobody has this part in stock. I wonder if it is because this part fails so rarely that nobody stocks it, or whether they fail so frequently, that nobody can keep them in stock. An estimate from the dealer to do the job was $700 for labor (plus at least $700 for the part). Gads. Looks like this will be another Saturday spent scraping my knuckles.

Ordered the new harmonic balancer pulley and a new belt as well. I must have come to the end of the internet, as I cold not find any thread, YouTube vidio, etc., showing how the harmonic balancer on this engine should be changed. Maybe I'll create a separate thread showing how I did it. Anyway, it didn't turn out to be as painful an exercise as I thought it would be. When I got the old balancer off, I was pretty glad I hadn't driven it since discovering the initial issue with the balancer. It looks like it is on the verge of complete separation. The new part (#6420300503) differs from the original in that it has 8 grooves for a wider drive belt, whereas the original only had 7. Bad news also is that the new belt I ordered came with 8 ribs, and would be perfectly compatible with my new harmonic balancer, but would not work with all the other pulleys in the system. As long as I was in there, I gave a spin on every rotating pulley, and concluded that my belt tensioner pulley is about to go as well. After hunting my local geography for a replacement, I decided to order one online, with another new belt. I ended up putting everything back together, running the original belt on the first 7 grooves of the new harmonic balancer, nearest the engine. Can't say that I feel altogether comfortable with this arrangement, but I guess under ordinary circumstances nothing should cause the belt to jump a groove and become misaligned. When my new tensioner and belt come in, I will tear into it and replace them as well. https://cimg5.ibsrv.net/gimg/www.mbw...722a2f69d8.jpg