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#1
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A/C - help trouble shooting, fixing
Hi all. I searched and searched, but could not find the right answer (not to mention when I search for "A/C" or "AC" no results show.)
My 1979 300TD n/a wagon has never, since I've had it, had a working A/C. Heat blows great, and blows well on A/C settings "hi" or "low" but nothing cold. Orig. owner mentioned the system needs to be recharged. If that is all that needs to happen, is there some way to confirm that it just needs to be recharged, short of just recharging it? I also notice the following when I put the A/C "on". The fan blows well, but when I push the "on" button for the A/C, and hold it in, some other fan kicks in, but does not stay on when I am not holding down the "on" button. Is there something wrong with the switch? Or bigger problems? I am trying to sell this wagon, but if I get the A/C working, may just hang on. Reason for selling - moving to very humid climate where A/C will be a necessity. Thanks.
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1979 300TD wagon (non-turbo) 266,000+ |
#2
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search and read all threads titled evil servo.
it's good your settings work in heat. and the fan works. does any air blow out the center vents when you set it to A/C and have the dial set to min? if not, go back to checking the evil servo threads. I had a 79 TD. fun little car. never got the A/C working. |
#3
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Thanks, will read the evil servo threads.
To answer your question - Air does come out the center w/ AC on. No dials on this one - my climate control looks like this -
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1979 300TD wagon (non-turbo) 266,000+ |
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#5
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OT: but wow thats the first diesel other than a coupe(300CD) i have ever seen with burl wood.
What is your VIN number?
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1985 300TD Turbo Euro-wagon 1979 280CE 225,200 miles 1985 300D Turbo 264,000 miles 1976 240D 190,000 miles 1979 300TD 220,000 GONE but not forgotten 1976 300D 195,300 miles 1983 300D Turbo 175,000 miles http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg |
#6
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Sorry, not a pic of my interior, just found online for convenience.
From this page - http://commons.wikimedia.org/wiki/File:Climate_Control_MB_w123.jpg Looks like it was uploaded from Germany, so possible a motherland-only special?
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1979 300TD wagon (non-turbo) 266,000+ |
#7
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Burl wood came on some early gasser W123's and on some early diesel coupes.
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1985 300TD Turbo Euro-wagon 1979 280CE 225,200 miles 1985 300D Turbo 264,000 miles 1976 240D 190,000 miles 1979 300TD 220,000 GONE but not forgotten 1976 300D 195,300 miles 1983 300D Turbo 175,000 miles http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg |
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Funny - I just noticed 79mercy and colincoon are in FL. I am hoping to get the AC working as I may be moving from Los Angeles to St. Augustine later this year.
Any chance you guys know a good MB mechanic in those parts?
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1979 300TD wagon (non-turbo) 266,000+ |
#9
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pierre
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92 300D 2.5L OM602 OBK #59 |
#10
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... that dial on the left side of the vertical buttons... blue numbers are cool. should have a min setting.
it's a very good sign that you have air out the center vents. your servo appears to be working. I'd have the system leak checked, and possibly, just head off issues, and replace the expansion valve, and charge it up and see if the compressor cools! |
#11
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does the compressor clutch lock up when you turn on the ac? you can't trouble shoot it if its empty. evacuate and charge the system w/ r134. all you need are the adapters to do this, don't let the shop tell you that you need all this new ****. have them put some dye in it so if there is a leak it will be easy to find. if you fill it and it works, done deal. if it don't work, put 12v straight to the compressor clutch to see if it will lock. don't leave it jumped for more than about 15 seconds, unless you have gauges hooked up, pressure can go way too high if there is a restriction.
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1984 300TD "MAX" 303K+ still going... fast '70 Chevelle 200k+ home built Shovelhead chopper |
#12
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DO NOT PUT DYE INTO YOUR AC SYSTEM.
It can stop up the Txvalve and other small stuff.. AND it will NOT HELP YOU FIND A LEAK IN YOUR EVAPORATOR.... Just say NO.... There are HUGE numbers of good threads which tell the proper way to do this stuff.... if it is probable you have a leak there is a legal way to check it.. in the archives available by using the search feature...
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1980 240d , chain elongation, cam marks reference: http://www.peachparts.com/shopforum/showthread.php?threadid=10414 http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html evap fin cleaning: http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator A/C thread http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html |
#13
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Here is what seems like a good game plan -
1) evacuate/flush system 2) replace expansion valve 3) recharge w/ Freeze-12 4) hope I get cold air! Since I am pressed for $$, would there be any harm in skipping 1+2 and just trying to recharge the system? Would be only possible loss be a few cans of Freeze-12, or would that cause other damage?
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1979 300TD wagon (non-turbo) 266,000+ |
#14
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" HOPE " is not really one of the concepts we use for dealing with AC systems... as they are really about pure physics. If you violate a rule it will bite you either with having to do it over again, or blowing your compressor or something else which will waste time and money ...
One was great. Two can probably be skipped if it is clean.. however, to do a proper flush you will want to use the old expansion valve as a ' tool' and so you will need a new one. Three is a very bad idea.. lots of threads about alternative refrigerants.. USE either R12 or R134a. If you are ready to accept those premises post and let us know.. we can get you to where you need to go in a logical manner... and will strive for ' as cheap as possible ,but not cheaper )... in other words... you can shoot yourself in the foot trying to cut too many or certain important corners..
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1980 240d , chain elongation, cam marks reference: http://www.peachparts.com/shopforum/showthread.php?threadid=10414 http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html evap fin cleaning: http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator A/C thread http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html |
#15
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Quote:
the flush will remove any oil from the lines/coils. there will then be no oil to speak of in the system, so putting fr12 in there will kill the compressor in just a few minutes... IF you are set to use fr12, you better get a complete kit with oil designed for the refrigerant blend. and you better put large warning stickers on the car showing freeze 12 blend is installed in the system! I would do this order. 1 flush and clean lines and coils. 2 replace the expansion valve. 3 pressurize with dry nitrogen and verify leak free system. 4 replace receiver/drier 5 add correct volume of correct oil to lines for the refrigerant used. 6 evacuate system to 1000 microns or a solid evac if no micron gauge is used. 7 recharge with correct volume of refrigerant. 8 start system and test operation of blower, aux fan, and check system operation. 9 enjoy cool a/c
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread "as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do! My drivers: 1987 190D 2.5Turbo 1987 190D 2.5Turbo 1987 190D 2.5-5SPEED!!! 1987 300TD 1987 300TD 1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere! |
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