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  #1  
Old 06-04-2008, 04:01 PM
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Increasing the efficency of A/C in a 123 240d

Hey all,

I am in Arizona, and its getting pretty hot already.

I am using the A/C and its keeping up, but its gonna get 15 degrees hotter than this in July.

When you have the A/C on, its pulling air from the inside right? (on a 123 240d)

Is there a way to recirculate the air inside the cabin rather than pull from the outside, so the air will already be semi-cool rather than trying to cool 115 degree heat?

In my old 126 300sd there was a flap to adjust to select outside or recirculate - does that exist on the 123 240d's?

Thanks for any advice!
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  #2  
Old 06-04-2008, 05:27 PM
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Your username says 81 300SD, but you are asking about a 240d.

What year ?

Manual controls for temp (dials like a Euro model ?).
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  #3  
Old 06-04-2008, 06:11 PM
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If you have the older-style manual controls with the AC knob (not the wheel thing), it does have a recirculator. It does not close off the outside air until the AC knob is turned about 2/3 of the way through it's rotation. The flap is under the passenger side kick panel, you can watch it move if you have the kick panel off.

This is from my '79 240D, so if you have a different model, It may not be the same.
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  #4  
Old 06-05-2008, 08:37 AM
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My username is 1981_300sd because that is the car I owned when I started on this forum. That car is long gone, and dont want to change my username when I get new cars

Mine is a 1982 240d, and it has the wheel AC control. Does this still have a flap that is under the passengers side kick panel? And does the recirculate turn on when the wheel is turned 2/3?

I have been doing some searching and it appears that even with recirculate on, its only 80% recirculate. Can I maybe just duct tape the flap closed so I can get a full 100% recirculate?

Im not worried about not getting enough circulation in the car, plenty of other areas in the car with air leaks, unfortunatly one of them is on the sun roof, but on the plus side it doesnt rain much here in the desert
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  #5  
Old 06-05-2008, 09:04 AM
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Location: Mount Holly, NC
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I don't miss that aspect of AZ living...

Does your system still use R$12? or have you or a PO converted it to 134?
is the condenser CLEAN CLEANCLEAN? aux fan working? have you gotten the back windows tinted? I would seal up that sunroof...
good luck with the outside air in issue, sorry I do not have more info in that area.
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #6  
Old 06-05-2008, 09:41 AM
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Ya the PO converted it to 134 Windows tinted, clean fins on the condenser, all that.

I even freeze a large water bottle while at work and when I leave for the day, I hang it in front of my vents to help out with the cooling lol.

Plus side of AZ tho, is that there are are very nice winters but damn its not in the summer.
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  #7  
Old 06-05-2008, 10:13 AM
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you have two choices aside from "fixing" the recirculation issue... replace the factory condenser with a parallel flow from a newer vehicle... or replacing the compressor and various sundries with new and putting it back to R$12
even when new, the factory R12 system was inadequate for AZ summer... hampering yourself with 134 is a bad thing...
do some shopping, and find yourself a can of 12 and get a replacement compressor and reciever and expansion valve
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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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  #8  
Old 06-05-2008, 01:25 PM
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Location: NY
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Either go back to R12 or replace the R134 with HC12. HC12 is more efficient than even R12.
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  #9  
Old 06-05-2008, 05:14 PM
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I agree with returning to R12 if you can. But to be honest on a car of that age I'd have to wonder if much can be done short of changing everything out. That includes the evap. Or at least cleaning it. I've often wondered about completely removing the entire a/c system on one of these and installing a custom after market one. One thing to think about is that the interior temperature of a car in Phoenix will get way hotter than 115 when it's sitting during the summer. So to permanently close your recirculation flap will have your a/c trying to cool down even hotter air than the outside temperature at least for a while after your vehicle has been parked for a while.

- Peter.
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  #10  
Old 06-06-2008, 04:14 PM
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Ya, I took that into consideration, but at work my car is in a parking garage and at home its under covered parking. So its usually as hot inside as outside when I use the car.

So how do you close the recirculation flap permanently on a 123?
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