Whats Everyone Else Doing For A/C Refridgerant?

[1972C10]

I just tryed Did the Swap to 134a and my local parts house screwed up one of the crimps on my hose So i have to take it back but even when i had the freon at its peak before discovering the leaking crimp It really wasnt to my expectations

Now R-12 just isnt happening unless i walk over and get a case From Taco Town And i dont see my border jumping anytime soon

I have read about several other types but I was curious to see what others with similar trucks have been using with what kinds of results

I have an 85 With a belt setup off an 89 and that style compressor I have all new parts including a blue orfice Using ester oil And still didnt seem to cool as good as i remember those trucks being but then again not 12

So whats everyone else Using ?

[gldevall]

255 here. Sometimes 260 or 270.

[bodydropped]

i converted my 78 to r-134a when after i broke my condenser when i swaped the engines out it would freeze u out when i use to drive it

[1976K5CHALET]

Personally for all of my own personal vehicles except the chalet i just spend the coin for the 12 at napa. However 134a does a good job. Problems usually arise in the amount added during the swap and thus causing less than desireable performance. The keep to getting our trucks to cool lies in the condensor at the front of our trucks. There are a few other mods you can due to a 73-87 to make it work a lil better. I lived in phx for 12 years and worked for freightliner for 7 of those years so i kinda have alot of a/c experience. Plus i own my own robin air machine a nitrogen bottle to check for leaks etc.

To date i know of no aftermarket company making a crossflow condensor for our trucks. In the old days if you had a delco a/c catalog you would see the condensor for a 80 k5 was different than a 80 burb with rear air. Why? The burb unit had for fins per inch to shed the heat with the rear air. Allthough the burb only with rear air model is not ava anymore...someone needs to bite the bullet and make a crossflow aluminum condensor that is a direct replacement for our trucks. Case in point head psi is where its all at. I used to drive around phx in my 79 K5 with a/c gauges taped to the windshield to see the difference in psi at a stop light vs. road speed vs. summer day vs. summer night. Even at night the head psi like to stay around 250 something. When that number comes down to the 150 - 200 relm things change dramatically when it comes to duct temp. Spray water on the condensor to help her cool down and at the same time watch your duct temp and the high side gauge...you'll see what i mean. Most modern semi's and vehicles run a cross flow alum condensor which does an awesome job of disapatting the heat.

As a general rule of thumb you fill an r12 system with 80 percent of the rated charge when doing a retro. But....thats not allways the case...watch your gauges and monitor your duct temp....thats what matters...not a set amount.

Tips.
Wrap the suction line with insulation with aluminized tape like ford did. Refridgerant at this phase is cold...why let the engine warm it up. Find a early 90's van...or look under the hood of your neighbors newer burb or tahoe....note what gm did with the accumulator...same deal...shields the can from heat. Glue some haet shielding material to the outside of the evap box where it faces the right side of the motor. Every little bit helps in the end result...cooler duct temps. Also the next tip has two ways to be done...it just depends on how you want to go about it. If you live in the mid to southwest you can simply cut the heater core line and install 2 ball valves to shut off all hot water to the cab...thus relieving the evap of added heat to deal with. A cleaner way to do it is to drill a small hole in the rain gutter and tee a vacum line into the fresh air vacum source used to close the flap in the cowl...run that to your newly installed vacum operated heater shot off valve. Note...mid to early 80's gm cars used this same method....

If the sytem is questionable or the oil is black (black death) when you tear down the system...you'll need to vist napa for some a/c system flush. Note...use rubber gloves and make sure when you blow it out you make some sort of catch can system that is covered as the stuff will eat plastic and paint.

Now that the system is clean what next? All though most of us can't afford this its truely the way to go to get years of service from our systems with out haveing to do it again. If you've experienced a system failure like the compressor coming apart...flushing and blowing out the condensor and evaporators will not remove all the metal in the system...period! So if you can afford it...replace them! Most parts houses in the southwest that deal with a/c parts only like APAAK in phx sell in line filters to protect your investment....i highly recommend the use of these filters. To little or to much oil can create and cause problems. To little frags the compressor...to much keeps the system from cooling just as to much refridgerant causes poor cooling. Go by the gm manual. They will tell you how much to put in the compressor and how much to add to the system for the coils. Most new compressors come with NO oil these days...prefill to gm's spec BEFORE installing said compressor! While we are in the relm of compressors....you pay for what you get. Years ago you could get reman A6's from azone for $59 bux. Good eal right? Wrong. After 3 in one summer i realized the $300 compressor from gm or delco was the way to go. Most remans are built by 4 seasons...and they own 2 or 3 more major names out there..so one is the same as the other. When they reman they slap them together from good parts from failed units...so sometime the balls and plates that move with the swash plates aren't to spec and the end result is just a matter of time. Yes a factory compressor is expensive...but just get the number from you parts man at the dealership and try these to save...gmparts direct.com-rockauto.com-ebay..they are our friends.


Well hope this helps.

DW

[Bill W]

I had my 91 suburban done by the shop two years ago and it is as cold as the R-12. At least my family complains how cold it is and you know how big a suburban is and I don't have rear air.

Bill

[Bowed]

Good write up ---1976 K5

[bodydropped]

my moms 89 burb has 134 in it and since its a large system it gets around 30degree on a thermeter and some times it blows ice

[1972C10]

I had a tard at the local parts house recrimp my hose fitting I flushed the systems again Installed another blue orfice And Recharged it and i am having better results now

I am going to get my factory AUX Cooling fan in proper working order and i think that will make it right It seems to blow better when im going down the road or if i have a large shop fan blowing into it So i think that cooling fan in the front will be the perfect solution

Now i just have to locate the relays and sensor for the aux fan .

But i think i will try to stock up on some R-12 for the next time i ever have to replace anything on it.