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A/C: do i need to replace compressor or entire system?
1982 Mercedes 300D
130k miles on odometer The whole story: Last year my a/c wasn’t working so I went to a friend’s house, replaced my receiver drier and expansion valve, vacuumed out my system and filled it with R-134a. My high side did not have a 134a adapter on it while my low side did, but my friend had 2 testers (one for R-134a and one for R-12) so I didn’t bother getting an adapter for the high side port. Well a week went by and my a/c stopped blowing cold so I bought a R-134a gauge set. (my friend lives an hour away and I didn’t feel like going all the way over there in the middle of the week.) I then bought an adapter for my high side port so I could read both my high and low side w/ my new gauge set. I tried to put on the high side adapter. No luck I went back and forth to the parts store, and destroyed 3 adapters before another customer told me I had to take the valve stem out for the adapter to screw on properly. Start reading here if you only want the pertinent information to my question: So late last fall I removed the valve stem on my high side port and screwed on the R-134a port adapter and as I was tightening it w/ a wrench SNAP!! The nipple on the hose broke off leaving my system wide open!! . Which pissed me off to no end because that seemed to mean I had to replace the entire hose. So I ordered a set of used hoses from a trustworthy source, and removed the hoses in my car (only the hose w/ the high side testing port and the hose w/ the low side testing port (because I could not break a nut)). Well I got the new (used) hoses in but it was late fall and a/c wasn’t on my mind so I did not install them. Here spring is so I decided it was time to start doing some research as to putting in my a/c hoses and getting the whole system working for the hot and humid D.C. summer Well in my research I found that leaving a system open like this (~6 months in my case) allows any freon still in the oil in the compressor to turn into an acid and destroy parts of my compressor. So I most likely need a new compressor Obviously I will need a new receiver drier Probably not a new expansion valve (this was replaced a year ago) My question: Can this acid destroy my evaporator and my condenser as well??! God I hope not! I don’t really want to look and buying a completely new a/c system!!!! On the other hand I don’t want to just slap the hoses and a new compressor in only to find out my evaporator and condenser are shot now!! |
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it won't cost much to evacuate and recharge the system as it is. leave the evac pump on for a loooong time. add an oil charge, then 134a and see what you got. if this fails move on to more expensive repairs.
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You really have only one option if you want to do it once and do it right. The reason is when refrigerant leaks oil leaks out with it. At this point you have no idea how much oil is in the system. So you have to flush out the whole system. It would even be a good idea to remove the compressor and drain the oil from it too. Then you can evacuate, oil and recharge with a new filter dryer. Then you will have a known amount of oil and refrigerant in a clean system. And it will work properly for a long time. That's the only way. If you try short cuts plan on doing it over and over or get crappy performance. Danny
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1984 300SD Turbo Diesel 150,000 miles OBK member #23 (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination |
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R134a is not recommended in the older MB air conditioning systems - the older A/C hoses are not linered internally to prevent R134a from seeping through. Also, if the system has had any possibility of moisture in it, I'd recommend checking the expansion valve for internal corrosion or trash, and replace it based on your findings.
Just completed repairs on my '84 300D turbo last Monday; replaced R4 compressor with new unit ($230), new expansion valve ($40), new pressure & temp switches($40-$50), and receiver/dryer ($88) - topped up with R12 & she blows nice & cold....R12 was $75/lb, but it's what was designed to run in the A/C system. And if your MB runs a low-mount R4 style compressor, don't even think about running R134a; the compressor will die a horrible death. I've commented on this in previous posts - Bryan |
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Jimmy L. '05 Acura TL 6MT 2001 ML430 My Spare Gone: '95 E300 188K "Batmobile" Texas Unfriendly Black '85 300TD 235K "The Wagon" Texas Friendly White '80 240D 154K "China" Scar engine installed '81 300TD 240K "Smash" '80 240D 230K "The Squash" '81 240D 293K"Scar" Rear ended harder than Elton John |
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Thanks Jimmy, but I try to support my local guys as well -
Compressor / New - $230 Rec/Dryer - $81 Exp Valve - $40 Pressure switch - $28 Had parts 30 minutes after calling them in |
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Lots to be said for having your parts in 30 minutes.....
__________________
Jimmy L. '05 Acura TL 6MT 2001 ML430 My Spare Gone: '95 E300 188K "Batmobile" Texas Unfriendly Black '85 300TD 235K "The Wagon" Texas Friendly White '80 240D 154K "China" Scar engine installed '81 300TD 240K "Smash" '80 240D 230K "The Squash" '81 240D 293K"Scar" Rear ended harder than Elton John |
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Fastlane website also said call for availability on R4 compressors -
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__________________
Jimmy L. '05 Acura TL 6MT 2001 ML430 My Spare Gone: '95 E300 188K "Batmobile" Texas Unfriendly Black '85 300TD 235K "The Wagon" Texas Friendly White '80 240D 154K "China" Scar engine installed '81 300TD 240K "Smash" '80 240D 230K "The Squash" '81 240D 293K"Scar" Rear ended harder than Elton John |
#10
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http://dieselgiant.com/repairyourac.htm
I get my compressors at Napa for the MB's and they cost about $106.
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1981 300D 147k 1998 VW Jetta Tdi 320k 2001 Dodge Ram 2500 141k 1979 300D 234k (sold) 1984 300D "Astor" 262k(sold) Mercedes How-To and Repair Pictorials I love the smell of diesel smoke in my hair |
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Brand new or reman? Also, is ebay the best place to run across Freeze 12? (R12 snobs, shhhhh)
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Jimmy L. '05 Acura TL 6MT 2001 ML430 My Spare Gone: '95 E300 188K "Batmobile" Texas Unfriendly Black '85 300TD 235K "The Wagon" Texas Friendly White '80 240D 154K "China" Scar engine installed '81 300TD 240K "Smash" '80 240D 230K "The Squash" '81 240D 293K"Scar" Rear ended harder than Elton John |
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Hit me back on the PM about R12...
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I'm not a doctor, but I'll have a look. '85 300SD 245k '87 300SDL 251k '90 300SEL 326k Six others from BMW, GM, and Ford. Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG] |
#13
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Reman. I only use them and never had a problem. Just make sure you use the BG oil to keep it alive.
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1981 300D 147k 1998 VW Jetta Tdi 320k 2001 Dodge Ram 2500 141k 1979 300D 234k (sold) 1984 300D "Astor" 262k(sold) Mercedes How-To and Repair Pictorials I love the smell of diesel smoke in my hair |
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R4 compressor photo attached - supposedly...
If the A/C hoses on your car are OE, then they will not be linered - Linered refers to a separate Nylon internal hose lining inside the A/C hoses - Low mounted R4 compressors will not tolerate the higher head pressures run when using R134a as a replacement. Also, I cannot comment pro/con regarding Freeze 12; I use only R12, as designed for the cooling system. Jiimy L - okay price on R4 @ $209... $21 delta in price doesn't hurt my bank account bnc |
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