I was pleasantly surprised to find that all it took to make the heating and AC fans in my 72 220D work after picking it up was to connect a vacuum line!

I was even more surprised when the AC compressor clicked on and I saw the clutch turning

Since no cold air came through the vents I decided to order some R12 off eBay.

After charging the system with approx 1.5 small cans the AC was blowing ICE cold. I mean, really cold and working well.

Heres what I've noticed after using the system for several days:

It works best on trips under 30 mins. After 30 mins or so, I'll notice the air is either cool but not COLD, or, the compressor will kinda freeze up for like one second causing the belt to omit a chirp. Sometimes the compressor will click on or off depending on how long I've been driving for. The aux fan comes on once the motor is warmed up and works just fine.

I believe the PSI on the gauge when charging said between 30-40psi (motor cool) at idle.

thoughts?

I'm not too nit picky with the AC functioning since I'm surprised it even does. I paid $750 for the car so this isn't going to be a situation where I dump too much into the AC system.

ALSO.. trying to change my hood star. Does anyone have any hints as to how to get the old, broken unit apart. I've got it off the car.......

Padded vise, a good set of diagonal cutter pliers, straight blade screwdriver, some "oomph" and a pair of needle nose pliers to guide the retaining pin in and out.

It's been a while since I've changed one but it seems to me you need to mount the entire ornament mount and all upside down int the vise (Star down), clamp the vise, grasp the end of the spring, pull up until the spring end hook clears the receiver socket, turn the spring hook 90 degrees,remove the retaining pin, turn the spring back to release the tension and feed the spring though the housing. Attach the spring to the new star and reverse the process.

The first time you do it is a real PITA. Oh hell, EVERY time you do it is a pain but it gets easier or at least less frustrating. There is a second spring casing inside the mount which needs to be depressed using the screw driver which I am pretty sure was designed by an S&M disciple merely to make you miserable.

An adequate supply of band-aids, booze and curse words will stand you in good stead.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

AC may be overcharged, not good if that is the case. What is the high side pressure? If it has the York compressor they were excellent but used a lot of power.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

How much power does having the AC running sap from the engine? Not sure whether I should try to fix mine or just yank it out since I've already had it disconnected for some time.

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1973 220D ~135k Mi
1979 Ford F100 300 I6 - 225k Mi

That old York "thumper" is a power sucker. If you intend to retain the A/C then switch over to a Sanden rotary compressor. Much more efficient and about 1/3 of the drag.

You'll need to have new hoses made up, an adapter plate ($50) and it would be a good time to replace the dryer.

We used to call the York an auxiliary brake 'cause every time it kicked on it was good for a drop in speed of 3-7 MPH.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Thank you! not sure WHY mercedes had to make these a rubix cube. I was having a good laugh yesterday because the plastic emblem on our 2012 GLK literally just pops off and the emblem on the 220D is literally impenetrable.

Quite a bit and my car has a OM616 swapped in so it is slightly more powerful than a standard 220D with a OM615. Honestly though these cars are so slow and I'm never trying to get anywhere fast while driving them so it really doesn't bother me. It is quite noticeable though.

Meh, this is more money than I'm willing to invest in a $750 vehicle. I actually purchased a Sanden kit and all the associated goodies for my much nicer 82 240D.

When I was researching compressor rebuilds vs a new compressor (glad I got a new one for my car), I found in some Denso literature that the Denso 10PA15 used in the 1986+ cars consumes 8HP, and that's not counting the additional load from the alternator driving the blower and aux fan or the cooling fan clutch locking up. I know it isn't the same compressor, but it should give some sort of insight into what kind of HP a compressor can consume.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Sounds like it may be freezing up the evaporator. There's supposed to be a "freeze thermostat" in there to kick the compressor off when the evaporator gets too cold. If it isn't working, the coil can freeze (literally) and will fail to provide cold air. It also sends liquid refrigerant back to the compressor since it failed to expand to a gas in the evaporator. If the compressor tries to compress liquid, it will hydrolock just like an engine. 30 minutes is long enough to cause the evaporator to freeze up if the "freeze 'stat" isn't functioning. You can test it in the freezer, or just replace it with an el-cheapo from a GM or something, they all do the same thing.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Need to check pressures. The compressor issue could just be a worn belt that can't fully drive the compressor. Could also be an over charged system, as said above. Undercharged is just as bad, as that will cause too low temps on the eveaporator and hydraulic lock, as stated above. The evaporator temp should be no lower than 35F to prevent icing. Since the AC works on pressure differential, if there is not enough refrigerant in the system, the high and low side will have low pressure, causing the low side temp to be below freezing. Say you have a 50F differential. Feels awesome when it's hot outside (100F drops to 50F), but once the inside temp is brought down to a comfortable temp of 73F, the evaporator is running at 23F and ices up. Get that differential to 40F and you have 33F on the evaporator at 73F.

Okay so I noticed two things today:

1. Drove home from the beach with the AC on the whole way (100 mile drive - 2 hours)
Worked fine, never got warm, never did the belt chirp thing

2. The belt itself looks loose. I don't think it can be tensioned since it appears the tensioner is self adjusting. Any info?

thanks!

IIRC not self tensioning. The bolts are loosened slightly on the idler pulley and it pivots on one of them adjusting the tension.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer