• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

A/C needs a charge

Burning oil said:
Got the new oil allready, waiting on the Compressor to come in.
Any problem using something else to flush the system?
Click to expand...

A/C flush also helps remove moisture from the system and leaves no residue.

Think of using something else for a flush and Warranty on compressor is in question. The compressor locking up is a start over process. (New accumulator and VOT plus the 134a charge with flushing it again...)

These old R-12 systems have enough problems on 134a as it is. I do not recommend using anything but a real AC flush product and a flush gun.

With that the only issue you should ever have is the compressor leaking around the body without becoming noisy or locking up. The only time I did not flush a system was from a leaking compressor. The new one failed and no courtesy warranty because I could not provide a receipt for A/C flush - I never will get a compressor from A GM dealer again. (It was 13 months old.) Lifetime warranty is the only way to go on these...
 
A/C flush is denatured alchol. Go ahead and waste money on flush. I have been using denatured aclhohol for a long time. They even smell the same. you'll notice most flush doesn't have the ingrediants on it. Just like sludgeout for oil tanks. Another ripoff. I completley disagree about r134a conversions. That is all I have done for the last 10 yrs atleast and had no problems. Just don't use PAG oil and it will be fine. I just converted a Ford L8000 not too long ago. It will freeze you out of the cab.Also you don't put the oil in the accumulator. You drain the compressor and put the amount oil in into the compressor through either the plug or the suction side. Most four seasons manuals have the amount of oil. Putting oil into the system can cause a temp blockage at the orifice or expansion valve while charging and damage the compressor. Esther oil can mix with any residue left in the compressor from the mineral oil used by the R12(years ago we used baby oil). 20+ yrs doing a/c work not to mention my Father was factory authorized service and installed for Mark IV, Doutherm and Coleman.
 
BTW A/C is very simple to understand. When you put something under pressure, it gets hot. When you release it, it gets cold. Think off openinig the drain valve on an air compressor. What happends ? The side of the fitting where the air is realsing gets frost. A/C works the same way except refrigerant gas has better propertiers and lubricant for this to happen. Some systems use orifice, some use expansion valve. Works the same basic way just regulated differently. I personally like expansion valves better. I have even custom built a/c systems.
 
Glad someone can clear up what is in the flush. I would read the warranty on the compressor first.

Most systems I have seen where the compressor burned up do not have the correct amount of oil in them anymore. Leaks take both the gas 134a, r-12 whatever and oil out of the system.

After a complete flush with a new compressor there is 0 oil left of any kind.

So I never trust the pour the oil out and measure... Course there is a get 2 oz out and add 4 in the instructions...

I use the accumulator as it can store the entire oil charge and meter it to the compressor through the hole in the pickup tube without risk of oil slugging the compressor. Not saying it is wrong but I am more comfortable with the accumulator method.

As far as 134a they run at higher pressures. You see the new compressor designs to deal with r134a vs the old R-12 compressors merely converted to 134a. This leads to the compressor body leaking before the compressor has worn out. Along with poor cooling from undersized condensers and a fixed orface tube. I have had a lot more leaks and 'service it every year' on R134a systems than I did with R12. Not that there is much choice anymore. The newer R134a systems work longer without the yearly service in my experience.
 
WarWagon said:
Most systems I have seen where the compressor burned up do not have the correct amount of oil in them anymore. .
Click to expand...

Precisely. As far as the warranty I have never bought a compressor from GM($$$$) I pretty much dealt with Four season NAPA etc. The only issue I have ever seen with warranty is proof that the reciever dryer has been replaced, in fact alot of auto parts store won't sell a compressor without a dryer. I thought about my earlier post and I feel the need to correct something. I have actually seen on some trucks that i converted the system was slightly less efficient at idle. The only systems I converted that "didn't work as good or get as cold" were the ones running those (IMO) POS Sanden/Sanyo throw aways. Some of the Peterbilts etc came through with them and they used a 6 cfm version which even with r12 was barely adequate. what I did with those was usually go through the parts book (I like books with pictures) and try to match up an 8 cfm with same mounting and if nessicary convert the fittings. After doing that found they worked good. I personally think the Old York Techumseh were the best. You could easily rebuild/reseal them and they took immense abuse and worked really good. Unfortunatley those compressors are hard to get and cost about 100$ more for a reman than a new Sanden so everyone goes Jap. Not to mention in a customized applocation the Sandens are easier to mount as they are small and light. The York/Techumsehs were the size of a briggs and strattton but damn they worked good. You take an R Model Mack with a 10cfm York on a Kaiser or red dot box and there would literally be frost on the windows. My Mack that I used to drive had a Sanden. when it puked I found the brackets to change to a York and it was night and day. I'm actaully going to build a system from scratch for my CUCV and I really wanna run a York but with the dual alts I think the Sanden maybe easier to mount . I picked up a nice NIB Mark IV underdash unit for it at the last swap meet. Also overlooked is airflow through the condensor. Very important to have a good flow of air or the system will not work properly. In fact I had an issue with an old Dodge Motorhome with a Mark IV Monitor(Big unit) and the compressor would lock up everytime we tried to charge it. It drove me nuts. I treid replaced everything. finally my father came out and ran a garden hose over the condensor and it didn't lock up. Turns out the Motorhome was missing the fan shroud and some moron put a flex fan on it and it wasn't drawing squat for air. Electric pusher fan solved the problem.
 
I ordered a 1.5 inch thick condenser today. Stock is 1" I think. The stock one cost $10 more than the 1.5" Do you think it will help?
So, i guess i will use denatured alcohol to flush and lot of compressed air to dry that out.
It will be a good time to clean the radiator also.
 
Good, this thing ought to do pretty good when Im done.
Buying a vac pump tomorrow as I have needed one for a long time.

My brother has a york (i think, came off a 70's ford) compressor powered by a briggs engine. He uses it as a vacuum pump.
 
The Yorks are highly sought after among the old Toyota Landcruiser crowd for on-board air compressors. Only a minor mod is needed to keep the oil in the crankcase instead of being pumped out through the AC system the way it was designed to do.

Don
 
So, is there any alternative to the AC compressor for 94-95? This is the flat big round rather flat compressor. I know the 96+ have a different one.
 
I think you would only be limited by the mounting. I have Vintage Air in two of my other toys. I love the Sanden thats on them. They are both expantion valve systems, will freeze you out of there. I would like to put the same Sanden on the 94, but just want the easy way out for now. I will eyeball it and see if it looks like it could fit.
 
Acesneights1 said:
I completley disagree about r134a conversions. That is all I have done for the last 10 yrs atleast and had no problems. Just don't use PAG oil and it will be fine. Also you don't put the oil in the accumulator. Esther oil can mix with any residue left in the compressor from the mineral oil used by the R12(years ago we used baby oil). 20+ yrs doing a/c work .
Click to expand...

Hey Kenny, I just looked and realized I have PAG oil It says its for R134a high viscosity. You are saying not to use it, but instead use an ESTHER oil, right?

Actually going out now to work on it, will check back in a few.
Leroy
 
With the new condenser remove the orface tube and shine a light in it to check for corrosion. Just returned one new that was full of white trash. Would have ruined the compressor PDQ!

No use the ester oil. It is compatible with any trace of R-12 oil. The r-12 oil settles out in a r-134a system and stops circulating anyway. PAG is for a virgin R-134a system.
 
WarWagon said:
With the new condenser remove the orface tube and shine a light in it to check for corrosion. Just returned one new that was full of white trash. Would have ruined the compressor PDQ!

No use the ester oil. It is compatible with any trace of R-12 oil. The r-12 oil settles out in a r-134a system and stops circulating anyway. PAG is for a virgin R-134a system.
Click to expand...

Thanks, just got back from parts store with the Esther oil. I will look at the new condenser also (good tip).
 
The '93 was the R12 stuff, i've got 2 of them and converted both to 134a. I usually exac and fill with exact amounts of 134, one of my trucks leaks a tiny bit and i have to top it off every 3 years or so. What i do with that, is put the engine at 2000rpm steady, lookup the temp/pressure/humidity charts and the low side when charged fully will usually be around 25psi at 2000rpm depending upon above conditions.
Don
 
Sorry , just saw this now. X2 on what Warwagon said. PAg Oil is ok in r134a systems that came factory. Converted systems should use esther oil That is where all the hype came form about conversions and having to change hoses seals etc. The first generation of attmepts at converting R12 to R134a had issues cause the littlest bit of mineral oil(what R12 uses) would create an acid reaction with PAG. In fact just today I changed the compressor out on my Dually and the old compressor had PAG oil. I dumped it in a pail full of used motor oil. Man it made some funny looking reactions. It was actually bubbling. I was like WTF ? Esther oil can mix with anything. I could have used PAG oil in my Dually since that is what it had but I don't stock the stuff cause I do mostly conversions and keep a good supply of esther oil on hand. Remember when filling a compressor, if you have not flushed the system completley and are just swapping the compressor like I did today then dump the old compressor out into a measuring glass and try to see how much was in it. I would not add more than 4 oz oil to a compressor that is going on a system that has not been flushed because some of the oil is in the system. If you have flushed the entire system and the compressor is ew and needs to be filled most GM compressors take 8oz of either pag or esther oil. I put 4oz in mine as about 3 came out give or take a touch.
 
midniteplowboyy said:
I thought 93 was the first year of 134a on these trucks?
Click to expand...

1994 was 1st R134A in C/K pickups factory. 1993 was R-12. GM did not change much from the R-12 design and the 'factory' 134a systems more or less sucked with 134a from the factory. 1993 should have had the barrier hoses that worked with R134a, yet the o-rings are wrong.

GM attempted some patches later like a electric pusher fan, bigger dash vents, and larger condenser. Only when they went with the driver side mount different design compressor did you get good cold air from the C/K pickups.

It wasn't until you added a better fan and a VOV that the performance came close to R-12 on the factory retrofitted systems. And that would not fix the undersized system that was marginal at best with R-12 in a Yukon w/o rear air. 134a and you were miserable in the rear seat and warm in the front.

The best patch was a lower turn on fan clutch like a hayden and an electric pusher fan wired to the AC clutch. More fan blades on the clutch fan would have helped too.

Before the VOV orface tube I have regretted using 134a in these systems esp. in the hot climate I live in. Disappointed in my 1st AC shop performed R134a conversion on a 93 c/k v6 PU and fought the a Yukon system forever. The idle temps of the VOV make these systems tolerable again. The pusher fan helped but the colder air after startup was found to occur with a hayden vs GM fan clutch. The GM clutch did not kick in soon enough causing a 15 min wait for the coldest air. Not fun in 115 weather.

The bottom line is R134a needs more airflow across the condenser than R-12 to keep you cool. No not same outlet temp degrees: keep you from breaking out into a sweat with the AC on high when it is over 100 degrees out. 110 out and AC gives up, 120 degrees and it takes a major mod to keep it cool because factory setup will not.

Edit to answer the other compressor question:
The newer driver's side mounted compressors are variable displacement and run all the time. Thinking you would change the belt drive brackets and climate control head and maybe the body computer to get that system to work as designed. Not worth the headache vs. a VOV and pusher fan added on to our old system.
 
You must log in or register to reply here.
Back
Top