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A/C Refrigerant capacity

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Camaronate

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Does anyone know the refrigerant capacity for a 1985 K5 blazer with 6.2 diesel? I am getting ready to charge my A/C tomorrow and I have not been able to locate this info. If I remember correctly it is 8 OZ of oil and 48 OZ of R12. I Will be charging with R134a and the system is new.

Nate
 
Camaronate said:
Does anyone know the refrigerant capacity for a 1985 K5 blazer with 6.2 diesel? I am getting ready to charge my A/C tomorrow and I have not been able to locate this info. If I remember correctly it is 8 OZ of oil and 48 OZ of R12. I Will be charging with R134a and the system is new.

Nate
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The heater box deal on teh firewall on my burb says the capacity. 4.8 lbs or something for a burb with rear air, might check that sticker on yours.
 
I will go look. Im not sure if it will be the same though, the truck was converted from gas to diesel. The A/C also went from the R4 compressor to the HR6 compressor.

Nate
 
Just went and checked, The sticker is there but whatever was on it is long gone. It is just a blank sticker now.
Can you fill and A/C system until the pressure on the manifold gauges are reading normal? If so I have gauges just need the high and low side pressures.

Nate
 
Camaronate said:
Just went and checked, The sticker is there but whatever was on it is long gone. It is just a blank sticker now.
Can you fill and A/C system until the pressure on the manifold gauges are reading normal? If so I have gauges just need the high and low side pressures.

Nate
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Thats my understanding, but i took mine in for service. Don't have the knowledge or the tools. So yah.

Don't take advice from the guy that didnt' do it himself.......:doah:
 
no thats a half ass way of doing it big time, the pressures vary depending on temp etc..., the only true way to do it is by weight. that being said any parts house should be able to tell u how much it holds. then u take how much r12 its suppose to hold and times that by .9 (i think it might be .88 for conversion) but .9 is fine and that is how much 134 u put in.
 
Don't worry, this will only be my second time doing my own A/C. The first time I just grabbed the autozone generic can with gauge and filled it up until it was cold enough. This time I went ahead and got the vacuum pump and manifold gauges so I could put the correct amount in. I also forked out for a brand new delphi compressor (very nice) so I don't want anything to happen to it.

Nate
 
make sure u evacuate it for a good long time, the moisture in the air mixed with refigerant makes acid which is not good for the aluminum at all.
 
chevyuser74 said:
no thats a half ass way of doing it big time, the pressures vary depending on temp etc..., the only true way to do it is by weight. that being said any parts house should be able to tell u how much it holds. then u take how much r12 its suppose to hold and times that by .9 (i think it might be .88 for conversion) but .9 is fine and that is how much 134 u put in.
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Yea, but if thats all you have than thats the way you have to do it. The store I bought the compressor from did not have the capacity listed. The 2.2x's rule for pressure to temp may be the way I have to go.

I did find a listing in napa for a 1985 chevy truck with R4 compressor listing it at 44 OZ of R12 and 8 OZ oil. That would be about 39.6 OZ of R134a, roughly equivilent to 2.475 lbs if my math is correct.

Nate
 
chevyuser74 said:
make sure u evacuate it for a good long time, the moisture in the air mixed with refigerant makes acid which is not good for the aluminum at all.
Click to expand...

Will do, The vac pump should be here tomorrow so I can evacuate it for a while and not worry about it.

Nate
 
i would evacuate for as long as you can, the hotter it is outside the quicker it takes too. an hour at the very minimum, we usually let em sit for 3~4 here but they are usually not in the way as well.
 
Yea, thats the one I just found, It only had the A6 and the R4 application. Should be real close though. I think I will start with about 35 OZ and go from there.
 
chevyuser74 said:
i would evacuate for as long as you can, the hotter it is outside the quicker it takes too. an hour at the very minimum, we usually let em sit for 3~4 here but they are usually not in the way as well.
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Does the vehicle need to be running to do this?
 
i always put a bit in then turn it on to fill the rest, for two reasons, one alot of times the vehicle wont take it all without the compressor running. and the second apparently u can liquid lock the compressor. something i have yet to do thankfully.
 
According to mitchell the shop program we use at work an 85 diesel k5 takes 1.53lbs of r12.. but i have a really hard time beleiving that.
 
Well, Have to wait to tomorrow to try and charge it. Had a bad leak, looks like the mating surface of the hoses to the compressor do not match very well. The other set of hoses are supposed to be here in the morning.

I think 44 oz is right, the 48 OZ could be for an A6 compressor.

Nate
 
I'm changing my accumulator this weekend and converting to R134. I have read it that you add 10% less R134 then R12. My 87 K5 will hold 3.25 so I will put 3 in it and call it a day. It likely has a leak but I'm going to convert it so I can charge it with dye and find the leak. I would leave the system in a vacuum for an hour though. If it has been empty for some time, or left open longer then 24 hours, change the accumulator too. Mine was $28 with no discount at Pepboys.
 
I just did the r134 change over to my '84 k5. Rent manifold gauges and vacuum pump at Autozone. 300 to rent then they refund the entire 300 when you return them. Evacuate the system, hold a 30hg vaccum for forty five minutes with the pump off to insure you don't have a leak, then turn the vaccum pump back on and run it at least 2 more hoursburn off any moisture in the system. Find a pressure table for ambient temps and charge.

My manual says 48 oz of r-12. I put in about 35 oz of r134. with readings at the gauges of 29 low side and 250 high side on a 100 degree day.

I am going to try to tune it a little this weekend. On 100 degree days in humid Houston, texas, it barely will keep me comfortable. I knew I probably could add more freon, but wanted to take it easy to make sure I did'nt blow anything. I replaced, hoses, compressor, o-rings, seals, accumulator and orifice tube. It all cost 350 bucks for everything.

Read up on it and learn how to do it yourself, that way you will not be spending a fortune on your AC. Face it, these trucks are old, and you will be in there often.

Also, work on your vents under the dash and seal them good.

The is a place on the web called ackits they have a forum that will help you out.
 
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