1989s with rear air: 42.3 oz or 40.5 oz?
#1
Archive Gatekeeper
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1989s with rear air: 42.3 oz or 40.5 oz?
OCD alert.
Per the TSB below, Up to June 1988 for S4s with R12 the capacity with rear air is 1200 grams, or 42.3 oz and without rear air it was 37oz or 1050 grams. Starting July '88 (89 MY) WITHOUT rear air was 950 grams or 33 oz but there is no spec for cars with rear air. By '91 I know it was 1150 grams (40.5 oz) but I dunno if that was true in '89 as well.
Can anyone with an '89 with rear air and the original refrigerant sticker on the radiator report if theirs says 40.5 or 42.3 oz?
Per the TSB below, Up to June 1988 for S4s with R12 the capacity with rear air is 1200 grams, or 42.3 oz and without rear air it was 37oz or 1050 grams. Starting July '88 (89 MY) WITHOUT rear air was 950 grams or 33 oz but there is no spec for cars with rear air. By '91 I know it was 1150 grams (40.5 oz) but I dunno if that was true in '89 as well.
Can anyone with an '89 with rear air and the original refrigerant sticker on the radiator report if theirs says 40.5 or 42.3 oz?
#2
Rennlist Member
I would stick with 42.3 oz. Some is bound to leak out over time by design and I would rather have those 2.7 extra ounces of refrigerant in the system than not.
#3
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Perhaps you didn't see the OCD alert?
I just don't understand why the spec changed with the '89 MY, it doesn't make any sense- The 5-speed condenser is the same from -87-91, the front evaporator is the same from 86.5 through early '93, the rear evaporator is the same from 85 through early '93, and the compressor is the same 87-89.
So the only thing that changed in the R12 era of the S4 cars is the compressor, but not until 1990. So why the freon charge change?
I just don't understand why the spec changed with the '89 MY, it doesn't make any sense- The 5-speed condenser is the same from -87-91, the front evaporator is the same from 86.5 through early '93, the rear evaporator is the same from 85 through early '93, and the compressor is the same 87-89.
So the only thing that changed in the R12 era of the S4 cars is the compressor, but not until 1990. So why the freon charge change?
#4
Rennlist Member
Nothing in the system changed in 89. Same compressor all the way back to 1980. The change happened in 90 with the new compressor design.
I think it is a typo. Albeit one that is less disastrous than the torque specs for the block drains.
I think it is a typo. Albeit one that is less disastrous than the torque specs for the block drains.
#5
Nordschleife Master
My 89 owners manual says 33.5Oz (950g) R12, or 40.5oz 1150g R12 with "additional vaporizer" on page 114 under Filling Capacities.
Pic below.. manual's part no. is WKD 928 021 89 dated 7/88
I assume the fluid capacity of the manual condenser is the same as the auto one? I wonder what the 928 SE owners manual says? They had the 10PA20C in 1988 model year - as its lighter weight.
For r134a capacities, refer tech bulletin 9501.
Pic below.. manual's part no. is WKD 928 021 89 dated 7/88
I assume the fluid capacity of the manual condenser is the same as the auto one? I wonder what the 928 SE owners manual says? They had the 10PA20C in 1988 model year - as its lighter weight.
For r134a capacities, refer tech bulletin 9501.
#6
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Oh the irony, it's right there in the owner's manual that I didn't read . Thanks Hilton!
#7
Former Vendor
It doesn't matter how much Freon you put in the system.
As soon as you turn on the rear A/C the front vent temperature will go up by 10 degrees.
Germans not so good at A/C, back then.
As soon as you turn on the rear A/C the front vent temperature will go up by 10 degrees.
Germans not so good at A/C, back then.
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#8
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It was actually a roundabout way of figuring out which sticker to make for the radiator. Can't have the wrong sticker...
#9
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Porsche did the best they could, but they just didn't have the condenser capacity to handle all of the evaporator volume.
#10
Former Vendor
Back then A/C was the only thing Americans had down. The old sealed units from the 70's would be the last thing to die on the cars and many would still work even in junk yards.
Porsche did the best they could, but they just didn't have the condenser capacity to handle all of the evaporator volume.
Porsche did the best they could, but they just didn't have the condenser capacity to handle all of the evaporator volume.
Need a team with doctorates in thermo dynamics to figure that one out.