My first post on this forum. I've had a 91 350sd for a few years and have not yet found a repair book for it. My a/c compressor locked up a few days ago shredding the serpentine belt and it would add much confidence to the job if I could purchase a manual. Any input appreciated.

https://www.startekinfo.com/StarTek/outside/12253/program/climate_350SD.htm

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CENSORED due to not family friendly words

thanks tjts1. i will try to decifer more from that site tommorow. BTW. theres no chance I lucked out and just have a bad clutch is there ? when I tighten the 10mm nut on clutch nothing will turn. when I loosen it clutch then turns. thanks in advance

Interesting that shredded the belt. There's an RPM sensor on the compressor and the compressor control unit should open the clutch if it detects any belt slipping.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

The compressor Speed sensor MUST match the Tachometer/Engine speed
sensor(s) information.Otherwise the HVAC control unit "C.C.U." will release
the Electrical power to the compressor clutch (Electro/Magnetic).Which is
supposed to "Save" the Serpentine Belt Which ALSO powers the Water Pump
and Radiator Fan.

In His Galactic Majesty's Imperium (Mr. Murphy,of "The LAW")
IT MIGHT be possible [I Guess ???] for both the Compressor Itself AND the
Clutch to go bad simultaneously ?

BUT would a bad compressor Clutch EVER Lock Up ?

I've (In my limited experience) only heard of compressor clutch failure
resulting in Lack of Engagement.

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'84 300SD sold
124.128

If you can turn the compressor freely by hand with the clutch loose, chances are its a
clutch issue.

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CENSORED due to not family friendly words

My tach has not worked on the car since I've owned it. It Explains why the belt failure going down the highway happened. I didn't know they were connected. Tried to get it fixed a few years back and the mechanic told me it couldn't be fixed. After towing this car 83 miles home I wish I'd broke down and bought a new one. Thank you for info.

If that's the case the compressor control relay was likely bypassed since it won't turn the compressor on until it sees the engine is at idle. No tach probably means no power going to the EDS unit. Does your ABS work?

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

abs works. No abs light on dash either. I'm not sure how to disengage the clutch ? turned the compressor off right when it happened on the highway. Now the only way to spin the clutch is when I loosen the 10mm center nut on the clutch. when I tighten it back it wont budge ? I hope nothing else messed up on the engine from belt breakage at 75mph ? thank you for your info.

any idea where to get instructions on this a/c job ? looked at tjts1 post for download but it had nothing on a/c compressor removal/instalation.

It's on there. Click more under sub function group, #83-522 removal and installation of refrigerant compressor.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Thanks for responding. I went to 83-522 and could not find my car ? Good instructions for 116 / 117 engines. Mine is a 603. Way difference in pictures.

The manual is a bit broken. Pick the 350SDL instead of the 350SD as your car.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

just tried 350sdl and it led me to the same sub-group ? I must be doing something wrong ? it keeps taking me to #83-522 ?
Thanks for helping this newbe.

MB actually pulled the 126 service manual from that site. They were having issues or something:

I asked about it and this was their reply:

"We had too many issues with the information as constructed. Please send VIN and what you are trying to do and we’ll send pdf. Sorry."
startekinfo.team@mbusa.com

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Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


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