Hey all. Car is a 2003 CL 600 with 95k miles. I've only owned in for a few weeks. Love it; just experiencing what appear to be some fairly typical problems. It's not my daily driver, so these headaches are a small price to pay for the experience of owning & driving such an awesome car. that said, here's my problem du jour.

The serpentine belt slipped off the pulleys last week while I was driving the car. Fortunately I wasn't far from home and was able to limp back to my garage without any of those nifty pulley-powered "accessories" -- like the alternator, power steering and ABC Popped the hood to confirm my suspicion that the belt was the culprit. It had indeed slipped off but appeared to be in good shape otherwise (except, perhaps, for the fact that it wasn't a genuine MB part, so I assume the prior owner had replaced it at least once -- but whether this was part of regular maintenance or a repair I have no idea.

Step 1: Loosened tensioner pulley and pinned it back per instructions; re-threaded belt around pulleys; everything looked OK, so I fired up the motor; everything seemed fine for about 20 seconds (if that); then the belt slipped again. Returned to drawing board, researched W215 and W220 forums and figured (duh), that it wouldn't have slipped off in the first place unless something else was wrong, so .....

Step 2: Went to dealer, bought new tensioner and idler pulleys (3), as well as new, genuine MB serpentine belt and installed all per WIS; everything looked OK, so I fired up the motor; everything seemed fine for about 20 seconds (if that); then the belt slipped again. Returned to drawing board, researched W215 and W220 forums and (duh) went back to check all pulleys for undue play, only to discover that the pulley @ the very bottom which is bolted to the crankshaft (aka the harmonic balancer) was loose. Really loose. Like stupid loose.

Step 3: Called dealer only to realize that they had closed for the day (i.e., the Saturday before Memorial Day). Realizing I was S.O.L. on getting one of those special wrenches to hold the balancer steady while tightening the bolt back onto & into the crank shaft. Returned to drawing board, researched W215 and W220 forums and (duh), decided to make a wrench of my own. Repeated re-assembly process of releasing tensioner, re-threading belt, and using said homespun tool to hold the balancer steady, torqued the bolt to the specified 100nm. Everything looked OK, so I fired up the motor; everything seemed fine for about 20 seconds (if that); then the belt slipped again. Upon inspection, I saw that the balancer which had been tightened to said 200nm spec was just as loose as before. As far as I can tell, it just unthreaded itself when the crank started spinning.

Step 4(a): Invented new swear words; uttered unspeakable things about the mothers of the sadistic German *******s who designed this wonderful machine (etc ....). Step 4(b): Smoked some weed. Really good weed. Step 4(c): Decided that things really weren't so bad after all, and maybe all I have to do is what I probably should have done in the first place (i.e., replace harmonic balancer as well, along with a new crank bolt and seal).

Step 5: Called dealer first thing this morning, only to find that there are none of the balancers available in the US. Shipping from Germany is going to take 5-8 business days :-(. Called local JY (which specializes in MBZ) to see if I could get a used one to tide me over. No dice.

Any guidance here, other than to repeat Step 4(b) until my part gets here? I guess I'm OK with that but thought I'd put it out there just the same. Thanks for reading.

 

do an online search.

 

Didn't find any better or quicker deals on the part. And I'm a little skeptical of some of the vendors. Even if they're selling genuine MB parts, different websites are suggesting different part numbers; I punched the part number provided by the dealer (i.e., 2750300003) into one site, and it tells me the part won't fit my car; punched it into another, and it directs me to part number 1370350200; another 1370350300.

 

some part #'s are interchangeable, or after market part#'s. buyer beware.

 

In my s class, you need to turn additionally 90 degrees after tightening to specific torque, are you sure that it is the only torque value given in WIS?