Hey everyone,

Yesterday, I tried my AC in the real heat for the first time. While the air was cool, the engine seemed really bogged down at idle with the compressor engaged,blower blowing etc. Is it normal for the ac to rob that much power or is something going on with my compressor.

thanks.

'78 240D 4spd

you might want to get some R12 charge oil (If you can get some) and add it into you A/C system , it should rob quiet bit of hp, maybe 3-6 hp. When i drive my 300SD I will always know when my A/C compressor kick's on.

Actros617

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Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

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1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

I would REALLY love to check the oil level, however, to do this requires an evacuation of the system, which I really do not want to do......

Even with evacuation of the system there is no way to "check the oil level".

The only way to ensure that the oil level is correct is to evacuate, open the system, flush completely, and add the precise amount of the proper type of oil for your refrigerant.

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Bob
'82 300D Petrol B-G Metallic

IMHO, your engine has only 72 HP (less at idle speed), so it will definitely notice the added load of the a/c compressor.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

My 240D has 63 hp, I'd love a 72 hp version :p

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1983 Mercedes-Benz 240D
Automatic, A/C, Power Sunroof, Power Right Side Mirror
231K Miles FOR SALE MAKE OFFER

I notice the compressor click on even on my 350SDL. The computer keeps the idle speed the same, but going down the road I can definitely tell when it's clicked on.

Has anyone ever looked into fitting a variable displacement compressor to one of these cars? They cost 4 times as much, but they don't cycle on and off.

-Jason

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

When the A/C was turned on in my 220Ds, it felt like I set the parking brake.....

A/C compressor, especially old ones like the A-4 you have, take a significant amount of HP to run.

Not a surprise you feel the drag.

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles

hi, i'm noticing the same issue with the 95 e300 i just picked up. is this normal? i'll try recharging the AC tomorrow. car runs strong until the compressor kicks on, which is always with this heat. any thoughts with regards to my application? thanks in advance

The question I have is what kind of refrigerant are you using? With the higher pressure R-134a, can virtually lock up (well not really.. but close to it!) a R4 compressor compared to using R12 refrigerant. If you have R-134a try switching to R4 or some other refrigerant that uses less pressure.

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1983 123.133 California
- GreaseCar Veg System

it's r134a, looks to be all original. the compressor all but stalls the motor when i put the AC on or when i come to a stop. i'd rather use the 134A since that's what's supposed to be in there, looks to me like the compressor clutch is tired. i'm definitely open to suggestions from other MB owners.

The large York compressor drains more power than the GM/Harrison compressor on the later models, you'll definitely feel the drain compared to that from the newer cars.

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so replacing the compressor with an updated model should help then?

That was a very good point. That compressor is a monster!



You would have to change brackets {large pain in the arse}, compressor, AC lines, wiring, and associated pulleys on the engine I imagine.....

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

I just went through something similar with my 86 SDL. The system was over-charged. Everytime the compressor kicked in, the car felt like someone threw out a boat anchor. Evacuated the system and then added the correct amount of R-134 and everything works just great !!

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87 300SDL - 215K Miles !!
99 F-350CC Dually PSD - 190K
86 300SDL - 189K
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