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#1
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1990 300E (124) A/C Help
Hi All,
I recently bought a 90 300E and wanted to convert from R12 to 134a freon. I've done it on my 86 300E and love it. I took it to the shop that did the conversion on my older 300E, they flushed the system and fixed a connection leak between the a/c line and the compressor. After changing the compressor oil they filled the system with the new 134a freon. Compressor started right up and the vents began blowing cold air, but after 2-3 minutes the compressor shut off and wont turn on again. The shop says everything was well, compressor sounded normal the air was blowing cold, then suddenly the compressor shut off. The shop believes its an electrical issue and wants a electrical technician to trouble shoot the problem. The shop said the pressure on both low/high sides were within normal range. Can anyone help? is there a fuse? Any suggestions? Thanks GP |
#2
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Are you saying that you did a conversion on an a/c system that was working okay?
I am not a proponent of converting 12 systems to 134a in general, but especially not a 124 car. It just doesn't have enough condensor capacity to be a good candidate. With the price R12 coming down and the price of R134a going up I just don't see the need of the conversion anyway. All that said, you need to start your troubleshooting procedure at the clutch connection with a voltmeter to see if it is getting actuation voltage. If it is, ohm the clutch to see that the coil still has continuity. If there is no voltage at the clutch connector, trace the circuit backwards through the r/d pressure switch. While testing all this, keep in mind that the climate control does not pull in the compressor for a few seconds after starting the engine to make sure that there is engine oil pressure before loading the engine with the compressor load. |
#3
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does your car have the mas relay over by the battery or a n a/c relay about the same size as the fuel pump relay?
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David S Poole European Performance Dallas, TX 4696880422 "Fortune favors the prepared mind" 1987 Mercedes Benz 420SEL 1988 Mercedes Benz 300TE (With new evaporator) 2000 Mercedes Benz C280 http://www.w108.org/gallery/albums/A...1159.thumb.jpg |
#4
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Since the summers in Michigan arent that long, 134a works fine here. I converted my 300D last summer. Since I knew the compressor was in working order and the system kept its charge, all I did was get the conversion kit (got mine from napa) from just about any parts store. Just follow the instructions.
It would be good to have a decent set of ac gages instead of the one that comes with the kit but it'll work fine. Mine works great ![]() I decided against continuing with r12 cuz they seem to be difficult to get a hold of while walmart carries 134 ![]()
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the sooner you start... the sooner you'll get done ![]() ![]() ![]() 2007 Honda Accord EX 2007 Honda Accord SE V6 96 C220 97 Explorer - Found Another Home ![]() 2000 Honda Accord V6 - Found Another Home 85 300D - Found Another Home ![]() 84 300D - Found Another Home ![]() 80 300TD - Found Another Home ![]() Previous cars: 96 Caravan 87 Camry 84 Cressida 82 Vanagon 80 Fiesta 78 Nova Ford Cortina Opel Kadet 68 Kombi Contessa |
#5
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I also have a 1990 300E that needs the conversion kit. Can you tell me what parts come in the kit. Your post does not mention any new parts as part of the kit. I live in New York City and was quoted a price of about $400.00 parts and labor. Mercedes dealers would charge about $700.00. Can you reccommend a major auto chain that can do a compentent job?
I found your post by doing a Google search. Thank you, kwelleri |
#6
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You can buy a kit as cheap as 20 bucks that has the refrigerant and oil as well as the adaptors. I wouldnt use it though. If I was gonna convert, which I would not, I would have a reputable shop do it the right way and just pay the good money to do so. It would be worth the extra cash.
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1984 300SD Orient Red/ Palomino 1989 560SEC 2016 Mazda 6 6 speed manual 1995 Ford F-150 reg cab 4.9 5speed manual |
#7
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I would suggest evacuating the old refrigerant first b4 converting by pulling vacuum then charging while it is in a vacuum.
I used a vacuum pump.
__________________
the sooner you start... the sooner you'll get done ![]() ![]() ![]() 2007 Honda Accord EX 2007 Honda Accord SE V6 96 C220 97 Explorer - Found Another Home ![]() 2000 Honda Accord V6 - Found Another Home 85 300D - Found Another Home ![]() 84 300D - Found Another Home ![]() 80 300TD - Found Another Home ![]() Previous cars: 96 Caravan 87 Camry 84 Cressida 82 Vanagon 80 Fiesta 78 Nova Ford Cortina Opel Kadet 68 Kombi Contessa |
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