AC feon capacity - PeachParts Mercedes-Benz Forum

sgt1959 · #1 06-15-2009, 08:56 PM

I have a 1987 sdl and recently retrofit the ac system new compressor drier etc the system was already converted to r134 but the sticker was erased that had the freon 134r capacity on it! does any one know the r134 capcity of freon for my 1987 sdl

dannym · #2 06-16-2009, 08:05 AM

I think the 134A charge is 80% of the R-12 charge.
Do you still have the R-12 sticker?

I think it's around 3 pounds which would make the 134A charge around 2.5 pounds.

Danny

sgt1959 · #3 06-16-2009, 08:36 AM

thanks for the response dannym no the r-12 sticker was previously removed

TX76513 · #4 06-16-2009, 08:55 AM

Here is the missing sticker

sgt1959 · #5 06-16-2009, 10:33 AM

so im reading this at 2.9lbs is that correct

TX76513 · #6 06-16-2009, 10:34 AM

Quote:

Originally Posted by sgt1959

so im reading this at 2.9lbs is that correct

Yes W 126 2.9 lbs (R-12)

sgt1959 · #7 06-16-2009, 11:24 AM

thanks much for all your help

leathermang · #8 06-16-2009, 02:47 PM

Just remember that it will work just fine several ounces ' low'... but ONE OUNCE above what it needs puts a real strain on the whole AC system...

Sometimes it is necessary/better to fill by high and low working pressures ( like if you have a bulk container but not an accurate way to measure the weight ).... but in that case you must be at high idle AND have a fan blowing air across the condensor and radiator.. ( almost certainly needs a squirrel cage blower to get the necessary flow.... and let it stabilize periodically to see that the readings are legit.

sgt1959 · #9 06-16-2009, 02:55 PM

that shouldnt be too much of a problem since ill be using 12 oz cans which if i use three of them should bring me somewhere around 2.32 lbs which as you say is a couple of ounces below its maximum limit

dannym · #10 06-17-2009, 08:01 AM

3, 12 ounce cans will get you about .07 ounces from where you want.

#11 06-17-2009, 02:12 PM

I would not start with 80% of the R12 volume. I would start with 70% of the R12 volume.

I recently beefed up my a/c equipment set and have been doing some auto a/c work again. I have been able to charge with a charging scale that lets me charge in 1/4 oz. increments. I read on an auto a/c sites where one of the guru's was recommending that you start with 70% and work up from there.

The condensor capacity and other factors make it different from car to car, but I've been amazed at how many cars are QUITE happy with 72 to 74%.

The goal is to make a converted system cool on the very least volume of 134 that will work.

In the past, charging with gauges and counting the number of cans, I could never get this precise and I overcharged. After seeing what I've seen with the charging scale and a little experimentation, if I were forced into using gauges and cans, I would charge no more than 70% and then start inching (ouncing) up from there.

The ideal method without a charging scale would be to block the throttle at about1700 RPM and put a high volume fan in front of the radiator and a vent thermometer in the center vent. I have an old squirrel cage that came out of a central heat unit that MOVES LOTS OF AIR.

With those conditions and initial charging done after your evacuation, put in two cans(24 ounces and then a little of the third can (looking for 32.5 oz as 70% of 2.9 lbs.)

Given that these cars have limited condensor capacity I THINK that it will be easier to overcharge than some of the cars I've been recently dealing with. Don't let your high side get over 250 at the VERY most.

I have been surprised at how little 134 it takes and am gunshy about overcharging. A converted system can easily get a runaway high side condition.

With the charging scale, after putting in the 70%, I inch up only 1 oz. at a time. It will be hard to know what 1 oz. is, but just put in VERY small amounts.

If you can't come up with a fan, put in the 70% or less and drive the car. If necessary put in just a touch more and do it in SMALL steps. Without the fan or the real life ram air, you will get artificially raised high side pressure and won't be able to tell where you're at with the charge.

Hope this rambling helps

jovyarcher · #12 10-05-2009, 08:45 PM

Quote:

Originally Posted by LarryBible

I would not start with 80% of the R12 volume. I would start with 70% of the R12 volume.

I recently beefed up my a/c equipment set and have been doing some auto a/c work again. I have been able to charge with a charging scale that lets me charge in 1/4 oz. increments. I read on an auto a/c sites where one of the guru's was recommending that you start with 70% and work up from there.

The condensor capacity and other factors make it different from car to car, but I've been amazed at how many cars are QUITE happy with 72 to 74%.

The goal is to make a converted system cool on the very least volume of 134 that will work.

In the past, charging with gauges and counting the number of cans, I could never get this precise and I overcharged. After seeing what I've seen with the charging scale and a little experimentation, if I were forced into using gauges and cans, I would charge no more than 70% and then start inching (ouncing) up from there.

The ideal method without a charging scale would be to block the throttle at about1700 RPM and put a high volume fan in front of the radiator and a vent thermometer in the center vent. I have an old squirrel cage that came out of a central heat unit that MOVES LOTS OF AIR.

With those conditions and initial charging done after your evacuation, put in two cans(24 ounces and then a little of the third can (looking for 32.5 oz as 70% of 2.9 lbs.)

Given that these cars have limited condensor capacity I THINK that it will be easier to overcharge than some of the cars I've been recently dealing with. Don't let your high side get over 250 at the VERY most.

I have been surprised at how little 134 it takes and am gunshy about overcharging. A converted system can easily get a runaway high side condition.

With the charging scale, after putting in the 70%, I inch up only 1 oz. at a time. It will be hard to know what 1 oz. is, but just put in VERY small amounts.

If you can't come up with a fan, put in the 70% or less and drive the car. If necessary put in just a touch more and do it in SMALL steps. Without the fan or the real life ram air, you will get artificially raised high side pressure and won't be able to tell where you're at with the charge.

Hope this rambling helps

we'll check on that. had no knowledge on the capacity of the freon but this post has helped mw worthwhile...