My air conditioning problem :( - Page 3 - PeachParts Mercedes-Benz Forum

1981_300sd · #31 03-02-2007, 04:50 PM

Yes, exactly. Hmmm great so now I dont know what it even has. Previous owners piss me off lol.

rrgrassi · #32 03-02-2007, 04:55 PM

I have the same problem. At least the PO used the blue cap for the 134 low side. That was the tip off for me.

You could buy one of those cheap 134 filler lines and see if it fits.

I have had plenty of PO/PO's excuse for a mechanic issues I had to correct.
I'm sure I'll find more. The one for my A/C was the high pressure line that runs under the front of the engine was spliced instead of replaced. A hose rebuild cost me $20 instead of $400 for a new one.

1981_300sd · #33 03-02-2007, 05:09 PM

Nice. When I first got this car, all the wires were all cut up and fuses shorted, and a ghetto wire was run from the stereo to the positive terminal of the battery. So therefore the door lock vacuum was not working. Spent maybe an hour connecting things correctly, and now the stereo, door locks, and all other electronics work fine. Took less time to fix than it would have to run that wire to the battery terminal.

rrgrassi, thanks for your quick responses. Did you see my question about verification of the high and low pressure ports? I am very concerned about this, because originally I took it to my local mechanic before I researched AC systems, and he took the low side reading, but I think he connected to my high side port - which was 45 PSI - now if he in fact read the high side, then that would mean I am way low on freon. I am going to verify this when I get my new gauges on there - I would be soooooo happy if all I had to do was recharge the system and not have to dive into the cooling system component replacements.

rrgrassi · #34 03-02-2007, 05:18 PM

Unfortunately, I do not know where the ports are on the '81. On my 82 w123 the low port is on top, just infront ofthe EGR valve. The high side is on the right side of the engine, near the alternator. If it is R134, the pressure corresponds with ambient temps. ACKits has a chart for this on their web site. If you do end up opening the system, when you evacuate it, do not use the Harbor Freight cheapo run by an air compressor. I learned the hard way. That thing could not vacuum dust off of a fleas butt.

1981_300sd · #35 03-03-2007, 07:42 PM

Ok just took the pressure readings. 85 psi high and 5 psi low. So should I go ahead and just try to recharge it? Does it sound like the problem is just low freon?

Thanks!

79300sdtd · #36 03-03-2007, 08:00 PM

do you know they type of freon? if you do there are pressure/temp charts that area available to get to the temp you want. in fridges the high side is like 130 and the low side is like 2-3. that is for 134a though.

if your compressor is turning you should just have to recharge it. then if it leaks out again you have to check your connections.

1981_300sd · #37 03-05-2007, 12:53 PM

Ok, problem fixed!!!! I am so happy to have AC again! The car has already been converted and was just very low. Recharged, and problem fixed. I am disappointed with the r132 performance, but am just happy that it works - I am just going to get dark tint all the way around. Between the two, I should be able to survive the summer

vstech · #38 03-05-2007, 01:31 PM

wow, so you just had low pressures... odd that this would cause the receiver to chill. hmm perhaps that may be why you are having problems... a receiver could be boiling off liquid due to the low pressure overall in the system and this would cause it to chill... still very odd. perhaps this is another reason why R134 does not work well in our cars. in addition to the serial condenser, the receiver may be a restriction.
John

1981_300sd · #39 03-05-2007, 04:05 PM

Ya I dont know. Does not make a lot of sense to me either, as now the receiver drier is warm to hot now. Im not going to complain though as I have 23 psi low and 210 high and is stable with cold air. Not the coldest, but thats why im looking for a tint job now

Thanks for everyone's help, greatly appreciated.

rrgrassi · #40 03-05-2007, 04:50 PM

Go to ACKits.com and look at the 134 pressure/ambient pressure chart. You may need to add more freon, or you may be just right.

#41 03-06-2007, 07:14 AM

Now do you understand why I ask for pressures from the get go?

Hit Man X · #42 03-06-2007, 07:23 AM

Quote:

Originally Posted by 1981_300sd

Ok, problem fixed!!!! I am so happy to have AC again! The car has already been converted and was just very low. Recharged, and problem fixed. I am disappointed with the r132 performance, but am just happy that it works - I am just going to get dark tint all the way around. Between the two, I should be able to survive the summer

Make sure you pick up the larger aux fan for the W126 (or the very late dual fans), this will help the A/C work the best it can.

Also, pull the radiator and blow the fins out with some high pressure water (it's gross, trust me) and try to blast the A/C condenser out too still in the vehicle.

The tint will REALLY help your inside temps, but don't expect any magic... you're down around 15-25% capacity now.

vstech · #43 03-06-2007, 07:48 AM

Quote:

Originally Posted by LarryBible

Now do you understand why I ask for pressures from the get go?

yes larry, you are, of course correct. live and learn.
John