8oz? Will this work? It has oil and a cooling booster. Or just 8oz straight oil? Should I make sure there is no oil in the compressor first and then add this stuff?

Buy Interdynamics R-134a PAG 150 Refrigerant Oil (8 oz.) GPH-6 at Advance Auto Parts

Ok. I found a vacuum pump that uses an air compressor at Harbor Freight for $16. Could I just use that? Then I would need to buy some manifold gauges. Still less than an hour of labor, which is between $90 and $120 an hour around here. None of the local stores have them for tool loan.

That just leaves the flushing process as the remaining issue. How can I do it without a flush gun and with just an air compressor? Also what is the best way to do it? Remove the orifice tube and accumulator, connect everything together bypassing the accumulator, put the flush solvent in one of the compressor lines and use compressed air until it comes out the other tube? Will that even work or would it just get stuck in the system? Thanks

P.S. I hate this type of repair where there are so many barriers to making it a DIY job.

 

Flushing the condenser and evaporator iindividually is generally part of the warranty agreement suppliers will have for replacement compressors. This may explain the reason better.

http://www.hecatinc.com/FAQ%20flush%...components.pdf

Pulling vacuum and then doing the static test is important also. Recharged a system once that I replaced the evaporator without pulling vacuum on and never got it to cool right, best I got was 65 deg. Took the car to a shop where they reclamed the 134a, pulled vacuum, replaced some O rings, tested again, (pulled and held vacuum this time) and recharged. After this the outlet temp was 41 deg. A clean leak free system is a "cool" one, LOL. This is one of the more difficult DIYs but can save you a few bucks overall. Good luck!

 

It's frustrating when something requires a lot of specialized gear. I bought one of those torsion bar key compressors when I did my last round of suspension work. I cursed having to buy it but once I did the job I was glad I spent the $100 on it because it meant not breaking my arm or ruining my suspension. Air conditioning is the same kind of thing. It's highly specialized and requires having the necessary tools for measuring pressures and dealing with gasses.

That looks like the right oil for your system. The factory specs are still pretty fresh in my head because I just did the a/c on mine recently. PAG is the kind of oil it is; 150 is the viscosity. The brand is pretty much irrelevant. You might want to go with oil that has UV dye in it so that if your system leaks in the future you can find it with a UV detector.

Flushing usually requires having a flushing gun. It connects to your air compressor and has a bottle that you put flushing solvent in and then pressurize the bottle with compressed air. That forces the solvent out of the bottle and through whatever component you're flushing. I have seen aerosol cans of a/c flushing solvent at AutoZone. If you don't have access to a flushing gun that may be the next best thing for you.

When it comes to flushing, do the components independently. Remove the accumulator and orifice tube and flush the evaporator separately. I like to put a piece of 3/4" heater hose over the outlet of the evaporator to direct the flushing solvent into a bucket. That keeps the job nice and neat. Do the condenser the same way. Remove the lines that connect to it and flush it separately. Because the a/c hoses from the compressor have a muffler built into the assembly you can't actually flush them. The best idea is to replace them with new. That will give you the best protection for your new compressor.

For further reading check out the fine folks over at Automotive AC Information Forum - ACKITS.COM. There's a lot of great information about automotive air conditioning and some amazingly knowledgeable people.

 

Ok, so I got the following and I might have to wait until the weekend to swap this out:

-Compressor
-Orifice Tube
-Accumulator
-Freon (3 Walmart brand cans)
-8oz (7oz oil/1oz "cooling booster") bottle of oil. Hopefully there is at least another ounce in the compressor...
-2 aerosol cans of A/C flush solvent
-Air operated vac pump
-Manifold gauges with can adapter

-Basic hand tools (will need to get a second adjustable wrench)
-Small Air compressor

What am I forgetting?

Yes, I did buy the gauges and pump, but all of this is still less than what anyone around here would charge.

So with the flushing, how does the procedure change since I have cans of it? How can I be sure I flushed it properly and how can I tell if all of the solvent is out? So why can't I flush the lines? I can see metallic particles in them.

 

O ring set for GM about 7 bucks and it has so many O rings will think you left 75% of them out but it covers all there modern car.

 

Yes, flush all the lines.

 

Flushing the condenser and evaporator is easy. Spray the aerosol flushing solvent in the top most opening in the component being flushed. Spray in short bursts. Once you've gone through about a pint of solvent the component should be clean. Let the component sit for a while (maybe 15 minutes) and then blow it out with compressed air to make sure all the solvent is out.

The reason you can't flush the lines is because one of them has a muffler built into it. The muffler is the small aluminum canister in the line just off the compressor. It's impossible to get all the flushing solvent and debris out of the muffler. It's like blowing all the loose junk out of an exhaust muffler. It's impossible. To do the best job that will last the longest you have to replace the lines with new clean ones.

 

Ok, so the air powered vac pump didn't work, so I had to buy a real one to finish the job. Noone had them for rent and I had to finish this today or wait until next weekend. I got everything working earlier today.

I flushed the condenser, evaporator and lines with 3 cans of flush solvent. System should be totally clean. Almost didn't get it all out even with tons of compressed air. I pulled a vacuum for 30 minutes to be sure everything (moisture and solvent) was completely out. The lines and condenser were easy, the evaporator took alot of air to clean out. No apparent clogs however. I drained the solvent into one of my oil drain pans and in addition to the solvent, UV dye and oil in it, there was a significant amount of metallic debris in there.

I found the probable cause of failure to be oil starvation. The compressor was clearly leaking for a while judging by the amount of oil covering the bracket underneath (I knew there was a leak somewhere for years but I never found out where it was until now. Here is my verdict.) and the clogged orifice tube with metallic particles says alot. The compressor must have been failing for months. The pulley was very very hard to turn and no oil came out of it even when removing the high pressure sensor ( had to move to the new compressor. Was fairly clean and in good condition.) and crankcase bolt.

After replacing the O-rings on all hoses I took off and the compressor, I also did the accumulator and orifice tube and added just over 8oz (5 in compressor, 3 in accumulator, about another ounce in the lines to make sure the compressor had all the oil needed to run. The formula had 7oz oil plus 1 oz cooling booster) of oil to the system before pulling a slight vacuum (.25 bar) which held for 2 days until I was able to get a better pump. Today I maxed out the gauge showing a full -1 bar for 30 min and let it go for 15 minutes with no issues. Added just over 2 cans so far to start and using an IR thermometer, the temp is in the 40s after a few seconds. The air is cool, but not ice cold. IR thermometer was even showing 30s, but that can't be right.

New compressor is silent and when driving I cannot even feel when it is on or off because the drag on the engine is just not there.

At around 80F, the low side is around 30PSI and high side is around 200. The temp was a bit higher earlier and I was seeing 40/270.

Thanks for all the tips. It seems all worked out. I did spend alot including on tools, but I still saved money compared to the mechanics. I guess I will be driving this truck often this week for A/C testing and parking the Trailblazer to keep the miles off it.

 

Congratulations on what sounds like a job well done! Now not only do you have working air conditioning, you have new skills and the tools required to do the job.

The clogged orifice tube was indeed telling. You had a compressor failure. That also demonstrated the importance of thoroughly flushing the condenser and evaporator. If there's debris in the system it has to be removed so it doesn't continue to cause problems.

Your system, like mine, should hold 28 oz. of refrigerant. If you used 12 oz. cans then you're probably undercharged by about 4 oz. I've learned that these systems are very sensitive to undercharging and will not perform at their best if not charged fully. The only way to be exactly correct about the amount of charge is to use a refrigerant scale, which you probably don't have. At the very least I would top off your system with a little bit more refrigerant just to be sure you're close to spec.

 

Well unfortunately it was short lived. I went to drive the truck today and was surprised to feel warm air out the vents. I checked the compressor and it was just cycling on and off every once in a while. I checked the pressures and the low side was around 20 (going up and down. Once the compressor kicked on it flew back to 10) and the high side was just over 100-150. I checked the high side port and found that there was a buildup of gas when I removed it. There was some debris in there that pressed on the valve briefly when the cap was put on, but I don't think it was leaking from there. The cap sealed the port well. I added some freon and there was no change, but after adding a little more than one can, the pressures stayed up at 50-70 low side and 300 to 500 high side which is maxing out the gauge and the compressor was only cycling briefly. I think my gauge set damaged the high side port because it is leaking a bit now, but the cap is sealing it. So what now? What other parts do I need to replace? In addition to replacing the pipe with the high side port (after having to pay someone again to remove the refrigerant), what else could be going wrong? What was funny was that I was seeing UV dye on the high side port, but that cannot be because I flushed it all out of the system and did not add more. The refrigerant I added does not have it.