Craig is right. Two pulleys increase the amount of surface area between the pully and the belts. Diesel's, such as are MB's, pull a lot of current out of the battery upon start up. There is a huge current drain from the glow plugs and then because our compression ratio is higher, the starter pulls more current. That is also why we have bigger batteries then the gassers. Therefore the alternator has a much bigger load in recharging the battery after start up.

TimK

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EPA 609 & 608 HVAC Certified
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83' 300D Turbo - 300K + Miles
00' 1.9L TDI Beetle
85' 6.5L Turbo, GV-OD, GMC Suburban,
67' 2.5L Diesel NA - Land Rover Series IIA

Here's what you do if it's so cold your diesel fuel gels. Smear some on some toast and stay inside until it warms up outside.

Then why do the non-turbo's have only one?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

So if I push down on them and they have lots of tension, and otherwise look fine, they're probably good? Especially if it is an intermittent thing?

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79 300SD - $50 out of pocket purchase
03 Dodge Ram 3500 CTD
2003 VW Jetta TDI

Did they get wet? If you drive through a puddle or something they will make noise.


Belts should be silent, if they squeal something isn't right.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Good question, did the NAs originally have smaller alternators? Maybe it was just an "upgrade" on the later cars?

I can't answer that. I don't know why my GMC Suburban with a 6.2L diesel came with a single pulley alternator set up either. I have found only one belt that will work on it and it has to be tight. It will last about a year. Once it starts to squeal it will never stop. Go figure.

TimK

__________________
EPA 609 & 608 HVAC Certified
_________________________________________
83' 300D Turbo - 300K + Miles
00' 1.9L TDI Beetle
85' 6.5L Turbo, GV-OD, GMC Suburban,
67' 2.5L Diesel NA - Land Rover Series IIA

Here's what you do if it's so cold your diesel fuel gels. Smear some on some toast and stay inside until it warms up outside.