300D A/C strike 3 - PeachParts Mercedes-Benz Forum

Crappy Gas Pipe · #1 04-30-2008, 06:01 PM

1984 Mbz 300D Turbo. 226k GreaseCar
27k miles ago when I bought the car to grease it, it had no belt on the A/C compressor. I had my indy put in a new A/C Compressor, Receiver drier, temp sensor the works. It ran poorly for several months and he added more R134a. Not impressed for some more months and then it blow up. Freon all over the left side of the car. $880 later its fixed again, this time by a Local Auto Shop. The old compressor was out of its 60 day warrantee and the new part is different now. More expensive. It works OK at highways speeds. Took the cardboard off the grill but AC is still just above poor. have to put some towels on the dash to stop defroster. . Does the button to the right of Defrost use the vents by the feet too? Those don't work. Why is this car on self destruct mode? Should I dump it before the AC goes again, next year?

BoomInTheTrunk · #2 04-30-2008, 06:38 PM

these cars suck with r134 in them get that out and get some real r12 or freeze12. also there are vacuum dashpots connected to the vents if the feet vents dont work then the vacuum diaphrams on those certain vacuum dashpots are shot and need to be replaced. you can get freeze12 off of ebay for way cheaper than anyother person is going to sell it to you for. you have already put alot of money into it and the a/c is almost prefect just keep it. Did the person that fixed it tell you the car ran with r12 originally or did he just put in the r134. i say this because i think you are supposed to flush the system before putting in the r134. that right there could have made something go wrong. if that was the case i would leave him at fault.

daw_two · #3 04-30-2008, 07:26 PM

I realize this is not the majority of the opinions expressed; however, 42 degrees F at the vent is pretty good. My 300D does it. Of course, I did all the AC work myself and I flushed the system VERY good from all openings. I replaced the compressor, drier, and expansion valve last summer.

tobybul · #4 05-01-2008, 06:16 AM

Quote:

Originally Posted by daw_two

I realize this is not the majority of the opinions expressed; however, 42 degrees F at the vent is pretty good. My 300D does it. Of course, I did all the AC work myself and I flushed the system VERY good from all openings. I replaced the compressor, drier, and expansion valve last summer.

can you tell us where you got the parts from? I think it matters what mfr is installed.

daw_two · #5 05-01-2008, 06:23 AM

Quote:

Originally Posted by tobybul

can you tell us where you got the parts from? I think it matters what mfr is installed.

Local branch of a national auto parts chain; AutoZone. I bought the oil though from NAPA. AutoZone had the flush canister and also vacuum pump that I could borrow FREE. Had to leave a deposit; but got it all back when tools were returned.

Followed the documentation from the dieselgiant website. This forum gave me the simple fix for the dash vents. In a 1985, the dash vents have the turn vent adjusters, so the pod arm can be slipped off. For heat, just clost the vent.

Crappy Gas Pipe · #6 05-01-2008, 04:17 PM

Quote:

Originally Posted by BoomInTheTrunk

these cars suck with r134 in them get that out and get some real r12 or freeze12. also there are vacuum dashpots connected to the vents if the feet vents dont work then the vacuum diaphrams on those certain vacuum dashpots are shot and need to be replaced. you can get freeze12 off of ebay for way cheaper than anyother person is going to sell it to you for. you have already put alot of money into it and the a/c is almost prefect just keep it. Did the person that fixed it tell you the car ran with r12 originally or did he just put in the r134. i say this because i think you are supposed to flush the system before putting in the r134. that right there could have made something go wrong. if that was the case i would leave him at fault.

Thanks for your help. The original was R134a and I I should look into the dashpots and not sure whats involved with the vacuum diaphrams. There is and arm behind the glove box that look messed up-for center vents. I forgot to mension I drove the car with ac on while there was a foam/cardboard covering the grill for winter. Maybe the system didnt get enogh air and blew up?

pawoSD · #7 05-01-2008, 04:18 PM

Quote:

Originally Posted by daw_two

Local branch of a national auto parts chain; AutoZone. I bought the oil though from NAPA. AutoZone had the flush canister and also vacuum pump that I could borrow FREE. Had to leave a deposit; but got it all back when tools were returned.

Followed the documentation from the dieselgiant website. This forum gave me the simple fix for the dash vents. In a 1985, the dash vents have the turn vent adjusters, so the pod arm can be slipped off. For heat, just clost the vent.

I think the problem has been found, Autozone parts are often of questionable quality....

ichbineinekrous · #8 05-01-2008, 04:32 PM

I've never seen anyone with one of these cars that had "great" a/c at idle, regardless of the refrigerant. It should be anywhere from somewhat cold to cool at idle though, unless you are in stop and go traffic and stopping more than you are go-ing. Sounds to me like the initial work was done shoddily, or perhaps just bad luck with the compressor. Some mechs. do not flush the system as well as they should, nor test the system by pulling a vac for long enough and checking for leaks. I also have had good results by following dieselgiant's procedure, r-134, synthetic poe oil, new compressor, expansion valve and dryer, and a thorough flushing. 44 deg at the vent. The middle button on the CCU seems to work the best, with the center vents rigged to stay open there isn't a huge volume of air coming from the defrost outflow vents.

AdvisorGuy · #9 05-01-2008, 06:04 PM

Mine is blowing about 55 degrees at idle and 40 on the move.

JimmyL · #10 05-01-2008, 06:17 PM

Quote:

Originally Posted by daw_two

I realize this is not the majority of the opinions expressed; however, 42 degrees F at the vent is pretty good. My 300D does it. Of course, I did all the AC work myself and I flushed the system VERY good from all openings. I replaced the compressor, drier, and expansion valve last summer.

Well heck, I get 40-41 out of the vents of China if the temps are below 80-85 {R134a}. The problem with R134a in these is that if it gets warmer than that then you aren't gonna get down that low. At idle for any length of time no freon will hold it's temp in these.
And in the dead of a Texas summer you aren't gonna get in the low 40's with R12 or Freeze12 with the stock W123 AC system. That would require I imagine a parallel flow condenser to achieve the lowest possible.
These cars just don't get as cold as most when the heat is really on......

Um, they should do a heck of a lot better than the original poster of this thread is getting......

BoomInTheTrunk · #11 05-01-2008, 06:35 PM

well if the condenser was covered when in use the system most likely overheated. The only thing that would get destroyed from the heat would be the compressor. replace the compressor and you should be good to go.

Matt L · #12 05-01-2008, 07:27 PM

Quote:

Originally Posted by BoomInTheTrunk

well if the condenser was covered when in use the system most likely overheated. The only thing that would get destroyed from the heat would be the compressor. replace the compressor and you should be good to go.

If you get compressor fragments distributed throughout the system, replacing the compressor gets a lot more involved. If you have a parallel-flow condenser, it will likely need to be replaced as you cannot flush these very well.

Search for "black death" to see what a problem this can become.

Crappy Gas Pipe · #13 07-02-2008, 09:02 PM

Matt L the new compressor was on for a minute or two and back to the shop it went. Blown compessor again. Black death syndrom maybe. Now my brake light is on and will spend another 900 buck for that. Its geting harder to break even with this GreaseCar. I just cant wait until diesel goes up to $10a gallon so I can justify having this clonker.

#14 07-02-2008, 09:19 PM

Maybe you should dump it before you kill it with grease.

My AC is 38F with R-12, I tried R-134a for about a year (until the compressor blew up) and was never happy with the performance.

Matt L · #15 07-02-2008, 10:30 PM

My AC is 38F at idle, recirculate off, fan on 4/7 (just over half). That's blowing pretty hard for such cold air, and that's 134a. My system is designed for that stuff and apparently it works pretty well. That's not all it's own fault. I was suffering from a restricted dryer for about a year before I tore into it.

Crappy, I bought a HECAT pulsating flush gun from www.ackits.com, and I can't recommend it enough for cleaning out your system. It's a lot better than the standard flush guns, as it sends bursts of fluid and compressed air through the part. The flush solvent is expensive, but there's no fix for that. It's important to eschew chemicals that will attack your oil, refrigerant or rubber lines.

I wanted the system flushed after 12 years of use and 200K miles, and didn't want to ask a shop to do it. For what they would have to charge for the job, I bought all of the tools and had enough money left over to have my existing refrigerant legally reclaimed, plus a bunch.