I learned this the hard way years ago...Contis are what the OEM spec is, they have made the belts for Mercedes for decades and there is a difference between them and other brands...just use Contis on your car and no others and you should be all set.

If, in an emergency situation, you need to use another brand it is OK temporarily but they just don't last for years the way the Continentals do.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

I went to my local NAPA guy a few months ago and asked him if he could get me belts "Made in USA and with Metric Dimensions" he assured me that he could, and did.....

The belts were NAPA/Gates.....
XL 7405......for water pump/alternator....sold as a "set" of 2
XL 9365......for AC Compressor
XL 9451......for Power Steering Pump

These belts have been on my car for just over 3 months, and 3,500 miles....they have not required any further adjustment.....

Belts running on multiple sheave pulleys should be purchased in "sets" that were manufactured on the same machine, in the same run, and can be identified by matching numbers molded into the belt......

SB

Note: I happen to prefer to purchase "Made in USA" products when possible, if my NAPA guy would have handed me a set of non metric belts, I would have gotten Continentals from my MB Dealership......

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Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

I suppose it's good to buy something made in the USA, even if it is just the $7 fanbelt for a $50,000 German car

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Just keep an eye on those NAPA belts; been there, done that.

My belts are MB (the ones that are on there), and they've got to have at least 70k of untouched miles on them. Still no squealing or problems, they are looking a little worn though. I'll replace them sometime soon with the German Conti belts I have had for a while.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

That's what I am running....XL 7405

I did have to go to two stores to get the set of belts. Maybe that is the problem. One does seem slightly tighter than the other. I'm going to add a lock nut to the adjustment bolt today just to make sure the alternator is staying put.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

If the double belts are mismatched or slightly different lengths all the torque or the vast majority of it is being transmitted by one belt. Also have a good look at the vees the belts ride in. If they are pretty rusty or the new belts are running on a rusty area I have had frequent adjustment problems on other cars with that problem and it is a pain.

The pulleys were rusty. They are nice and clean now after all that slipping!.

I tightened them a bit tighter than I usually wound (like to run them fairly loose to go easy on the bearings of the belt driven accessories). So far so good.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Biggest problem I had was some of the bolts were so tight, I couldn't break loose, after two days of soaking in PB blaster, without fear of doing damage. Mechanic took care of it, if they broke it, they would of had to replace, and they have a lift, put a pipe on it etc.

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83 SD

84 CD

Sometimes nothing other than heat will allow things to move along.

I have been running a Gates serpintine belt on the SDL for 2-3 years and its fine, no strange wear patterns yet. I got ripped though, I paid $40 for it at the local store, could have gotten it cheaper from the dealer.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Best belts are from Bando, Japan, outlasts everything else including Gates and Continental I have used previously, although Continental didn't do as bad as Gates.

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99 Gurkha with OM616 IDI turbo

2015 Gurkha with OM616 DI turbo

2014 Rexton W with OM612 VGT

I have a bando serpentine on my 124. I like it so far, but mine has the automatic tensioner so I won't know of a problem until it fails or starts making noise.

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Muleears
'07 E320 Bluetec 133K my DD
'04 Jaguar XJ8 VDP, 34K
'10 Hyundai Accent 60K Grocery Getter
'02 VW Golf soon to be on the road again
'97 E300 Diesel Son's DD
'61 VERY tolerant wife

Hampton Roads, VA USA

Gone but not forgotten:
'67 250S 95K
'86 300SDL
'87 300D Turbo, 364K! R.I.P.
'98 E300 Turbodiesel, 213K
'02 S420, 164K
'01 Prius 138K

Bando ran for 7 years of extreme climate with the vehicle parked outside, it still hardly needed adjustment but was getting dryer, in my experience, it would go dry before it would rip and that too in a long time.

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99 Gurkha with OM616 IDI turbo

2015 Gurkha with OM616 DI turbo

2014 Rexton W with OM612 VGT

I own/drive my car because it's a Diesel, not because it's a Mercedes, and it cost me way less than 50K.......if the "Powers that Be" in Detroit would manufacture a small Pickup with a Diesel that gets 40 MPG or better, I would not be looking for an early '80's VW Caddy.......with solid shock towers.....!!!

SB

Please Note: that I like German engineering, but my primary reason for owning Diesel vehicles is that I am also running Bio-Diesel, and therefore my fuel is "Grown and Refined in the USA" and not pumped out of the ground somewhere in the Mid East......

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Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG