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#1
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Cold air instead of heat 1979 300D
MB mechanic did by-pass on heat, it was working, now blowing cold air. Any suggestions? Thanks...T.C.
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Thanks, T.C. 1979 300D non-turbo silver |
#2
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Find out what he did to bypass it. I'm not sure, but you may have the servo unit ( ), someone else can chime in here. If not, the monovalve ( ) is easily "altered", or rebuilt. Also, if it stopped suddenly, you may want to check your coolant level. Low levels will reduce heat.
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1989 300E 144K |
#3
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79 has the servo. You need to figure out how the bypass works and how the flow of hot coolant to the heater core is controlled. It could be that there is a valve and the valve is closed. If you get heat at high speed, it could mean that the auxilliary coolant pump has failed. Could also be a bad thermostat. What is the temperature guage showing?
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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 |
#4
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Here is your servo info. Enjoy!
http://www.imperialclub.com/Repair/Lit/Master/281/index.htm
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"Our Lady of Blessed Acceleration... don't Fail Us Now" |
#5
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1979 300D does have the servo
I think that the servo was mechanically by-passed but not physically (second new re-maned servo from German Star in 2 1/2 years) . The auxillary pump is not hooked up. The heater hose that runs along the fire wall has a valve in the middle. Open for heat, closed for AC. This valve used for the by-pass is alright, still a little heat will come out sometimes when I first start her up for just a few seconds and then just cold air! Blower works great new MB part 2 years old. Heat only works on defrost which I understand means a vacuum problem within the system?
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Thanks, T.C. 1979 300D non-turbo silver |
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