How realistic is fixing the a/c? (83 300SD) - PeachParts Mercedes-Benz Forum

83w126 · #1 06-08-2013, 04:23 AM

It has been over 100 here for the first time this year, so I was thinking about how tired I am of driving a car with no a/c.
I haven't done anything with the climate control at all on this car since I bought it, and it pretty much doesn't work at all. The fan doesnt do anything at all (I think someone tried to rewire it didnt do it right) and if you set the temperature all the way to hot the heater will work, or if you turn everything off the heater just turns on and off for no obvious reason. And it has probably been at least 20 years since the a/c was working. The only good thing is that I think other than the blower wiring there isnt actually anything missing.

My thought is that it would be at least $3k to fix, and require buying another car to drive while I fixed it, so I would be better off just selling it and buying something else that the a/c works already, but am I making it more complicated than it actually would be?

leathermang · #2 06-08-2013, 10:46 AM

Unfortunately the latter is probably true ( sell, buy AC working car )....... read the AC threads closely... if you go for fixing go with a Sanden conversion if at all possible...

pawoSD · #3 06-08-2013, 10:51 AM

Probably not 3k to fix, but I'd figure around $1500 to be safe.

mach4 · #4 06-08-2013, 10:53 AM

Quote:

Originally Posted by 83w126

It has been over 100 here for the first time this year, so I was thinking about how tired I am of driving a car with no a/c.
I haven't done anything with the climate control at all on this car since I bought it, and it pretty much doesn't work at all. The fan doesnt do anything at all (I think someone tried to rewire it didnt do it right) and if you set the temperature all the way to hot the heater will work, or if you turn everything off the heater just turns on and off for no obvious reason. And it has probably been at least 20 years since the a/c was working. The only good thing is that I think other than the blower wiring there isnt actually anything missing.

My thought is that it would be at least $3k to fix, and require buying another car to drive while I fixed it, so I would be better off just selling it and buying something else that the a/c works already, but am I making it more complicated than it actually would be?

I think that you stand a good chance of being able to fix it for a lot under $3k particularly if you reasonably handy. And there should be nothing that you would do in that process that would render the car undrivable during the process.

The good news is that you've got a 617 so you can use a current technology Sanden compressor which you can source online for as little as $150 or so. You can get the adapter bracket from Rollguy for $200 or so. A new drier can be as little as $25. An expansion valve is as little as $25 or so. You'd need to get one or two hoses made up which can vary depending on the shop you use. You'd be well advised to replace the expansion valve. So assuming that the system is "clean" that's what you're facing. Each item can be done independently and will not take the car out of service.

The first step however is to assess your existing system. If the compressor turns freely, there is a good chance your system will be clean. To find out remove the compressor and dump out the oil and see what it looks like. What you're hoping to not find is black oil with particles in it - as that's "black death" and would require a complete system flush or possibly replacement. If the oil is decent you'd still be advised to flush out the condenser, lines and (while you've got the expansion valve out) the evaporator.

Then you can button up the system, vacuum it and install a suitable refrigerant. There are lots of choices. My personal choice is Envirosafe, but refrigerants are like oil, antifreeze, air cleaners, filters, etc. You'll get as many opinions as people you speak with, often quite aggressive. Do your own research and choose what's best for you.

You can charge your system yourself, with just a low pressure gauge, but if you've done all this, a set of manifolds are definitely worth it.

So you can evaluate your system pretty simply and tackle it incrementally bailing out at any point you feel you're over your head or it's just too much.

I'd probably focus on the blower first as that can be a bit of a project and your A/C system will be pretty much worthless without a good blower. Lots of info on this site, and plenty of parts in the junk yards to replace broken or missing components. And you might want to check your monovalve too. A leaking monovalve will hurt A/C performance significantly.

Good luck

83w126 · #5 06-08-2013, 05:21 PM

Would converting to the manual european style climate control be cheaper/more reliable than fixing the system that is in the car? I dont know how much is different, but I see euro w126s in pick and pull often enough that getting the parts wouldnt be a big deal. Since the heater in my car turns on and off by its self even when its supposed to be turned off I dont really trust that any of it is working properly anymore.

pawoSD · #6 06-08-2013, 07:10 PM

Quote:

Originally Posted by 83w126

Would converting to the manual european style climate control be cheaper/more reliable than fixing the system that is in the car? I dont know how much is different, but I see euro w126s in pick and pull often enough that getting the parts wouldnt be a big deal. Since the heater in my car turns on and off by its self even when its supposed to be turned off I dont really trust that any of it is working properly anymore.

That would be a pain, I would just source a good working used or buy a rebuilt (under $200) climate unit.

mach4 · #7 06-08-2013, 07:59 PM

^^X2 or get one at a junk yard and hope for the best.

Waste_Gate · #8 09-13-2013, 02:06 PM

It just so happens I'm in the middle of an A/C job right now and came up with a list of what I've spent money on.

This is basically for a full rebuild minus the evaporator and condensor. This list assumes you are replacing the compressor and are keeping R12 in the system.

The receiver/drier I got here from pelican was NOT ruined when i got it but I ruined it myself by exposing it to atmosphere when i opened the caps

Willson
85 300CD

daw_two · #9 09-13-2013, 04:39 PM

Quote:

Originally Posted by 83w126

Would converting to the manual european style climate control be cheaper/more reliable than fixing the system that is in the car? I dont know how much is different, but I see euro w126s in pick and pull often enough that getting the parts wouldnt be a big deal. Since the heater in my car turns on and off by its self even when its supposed to be turned off I dont really trust that any of it is working properly anymore.

I'm parting out a 240D with all the manual climate controls; dash is already pulled.

eatont9999 · #10 09-14-2013, 12:00 AM

I rebuilt my A/C and it may have cost me close to $600. I bought a 30Lb tank of R12, though. If you can do the work yourself, it won't be anywhere near half of $3000. I also bought a new compressor and an upgraded condenser. I bought a new (larger) condenser fan as well. Once you finish the job, you will realize that it is not as bad as you thought it would be. Ask me any questions you want.

Upgrading to a Sanden compressor is nice but I could not justify the large price tag associated with just that one piece. You can get a USA made R4 compressor from AutoZoo for under $200. The brand is Compressorworks.

eatont9999 · #11 09-14-2013, 12:05 AM

The A/C in my 300SD is twice as good as the A/C in my Fiancee's 04 Mazda 6. Granted Jap cars have crappy A/C most of the time. Mine keeps up well with the 100+++ Texas heat. Anything under 80F and I am afraid to turn the A/C on because it will get too cold. On humid days, I have condensation dripping off the vents.

ROLLGUY · #12 09-14-2013, 01:32 AM

I have done several 123's, and one 126 with the Sanden upgrade. The total cost for all the parts is less than $600. Yes you could get a new R4 from Compressorworks, but I doubt it will last more than a couple seasons. Before I started producing the Sanden retrofit bracket kits, I bought a new R4 from O'riley and installed it and had it charged. It failed moments after the charge was complete (done by a professional shop). I then got one from AutoZ..., and it was defective right out of the box. I decided I had had enough with the R4, and set out to make an adapter for a Sanden. The rest is history. I am biased here, but I will offer my opinion anyway

.
The Sanden compressor is quieter, smoother, takes less horsepower, is more efficient, and costs less in the long run than an R4. My first Sanden upgrade was done on my former 84 SD using a $40 USED Sanden style compressor, and it is still working great today (my friend Tony loves this car!). As others have said (and I agree), keep the SD and fix the A/C. It will NOT cost anywhere near $3,000!.....Rich

97 SL320 · #13 09-14-2013, 09:45 AM

Rather than battling 30 year old parts I'd:

Look at a old style under dash unit or similar, a modern compressor and new condenser. Places like Vintage Air sell all sorts of kits / parts for street rods and such. If you are not worried about cutting up a Pebble Beach winner, this would be the way to go.

Codifex Maximus · #14 09-15-2013, 04:22 AM

I figure I'm going to keep my W123 300TD wagon so I'm dreaming of a new AC system.

Current system R4 squeals like a stuck pig and only cools moderately.

ROLLGUY's SANDEN kit is what I'm thinking of. Just got to get the mula together. I want ICE CRYSTALS coming out of the vents and my passengers complaining that it's too cold. I said I was dreaming didn't I?

So many goodies to buy and so little money to do it.

eatont9999 · #15 09-15-2013, 09:35 AM

Quote:

Originally Posted by Codifex Maximus

I figure I'm going to keep my W123 300TD wagon so I'm dreaming of a new AC system.

Current system R4 squeals like a stuck pig and only cools moderately.

ROLLGUY's SANDEN kit is what I'm thinking of. Just got to get the mula together. I want ICE CRYSTALS coming out of the vents and my passengers complaining that it's too cold. I said I was dreaming didn't I?

So many goodies to buy and so little money to do it.

I get complaints about the A/C being too cold, even on a hot day.

My main complaints about the R4 are that it puts a large load on the engine and it is known for a short lifespan.

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