No, haven't gotten to the AC fix yet. I was doing some preventative maintenance on my other daily-driver, a 1982 Prelude. (ONLY 208,000 miles)

I'll be doing the AC sometime next week. This weekend is for sailing.

BTW I think I got the same kit as you. I also ordered a condenser, just to be thorough along with some flush chemicals. I wanted to make sure the hoses are clean in case the old compressor had been pumping crud through the system. I also will be borrowing stuff from AZ.

Any other advice you could pass on now that you have done the job?

I'll report back on when mine is done. I really want to get it done as it is getting warmer here; the upper 70's! Well, warm for springtime in norther Idaho! LOL (Come August we routinely touch 100'F so the AC is very welcome then.)

 

No, I didn't do a flush or anything. If it was for me and I knew I was going to be driving it for a few years myself, I would have done that and the condenser too, but it's for my HS age kid. Was a pretty simple job to do really. I followed the A/C threads in here, and it was right on. Didn't have to use the spacers for the compressor. It must be a little bigger pulley or up a little higher, because the tensioner is definitely tighter now. Still fit just fine. Just make sure and lube up all the O-rings when you put them in. Sounds like you have a good plan in place.

 

Again, this helps put things into perspective for me as I do hope to keep my truck on the road for several more years so my wanting to do the flush and replace the condenser would be appropriate. Thanks!

 

Basics for compressor replacement if you want to learn how to do it right or want to know if the shop is going to do good work:

If you have been losing refrigerant now is the time to find out where, If the system still has a charge in it then inspect all connections for oil, those are leaks. If you have a detector then sweep around to locate the leaks. check the evaporator, condensor, compressor, accumulator, tvx valve if it has one and all connection points. Try to do this with everything dry on the outside, condensation confuses some detectors. If there is no charge in the system then charge it with nitrogen and a trace of refrigerant first. Those components, orings, or schraders need to be replaced while you are doing the work.

If there is a charge in the system, have it recovered, do not vent it to the atmosphere. It's illegal and carries a scary big fine, even jail time is possible. The EPA pays people to turn you in so it pays to know the law. If you want to completely follow the letter of the law then get your section 609 cert for working on vehicle AC which you can do online for free. This is the site that I used:

https://www.epatest.com/609/openbook/

and you will need a lot of equipment.

Make sure that the oils are compatible and the correct weight for that compressor and the existing system. Check the plate in the engine compartment for existing. Note if the replacement comes with an oil charge or is dry. All of this is usually on a tag on the new compressor. However much oil comes out with the old components is the amount that you leave in the new compressor to keep the system oil the same. Pour the oil out of each removed component to asses how much oil has left the system. If you forgot or spilled it, there is a chart. Pour the oil out of the new compressor and return the amount that was lost, or add that amount to a dry compressor. Some people advocate just leaving the whole oil charge in the new compressor regardless of how much came out of the old parts. Under certain circumstances this can result in too much oil in the system but is probably OK for most repairs.

Flush if the system got contaminated with a compressor burnout but not necessary otherwise. You would see that at the orifice tube and in the compressor oil. Do an acid test on the oil if your not sure. Iv'e never had to do a complete flush and I have a repair with 100,000 miles on it. In this case you would leave the entire new compressor oil charge in the system. The absolute right way here is to distribute the oil charge into the components using the charts that show how much where.

Always replace the orifice tube or filters if equiped, its the right thing but also your compressor warranty may require it. Confirm the orifice markings. Also you must replace the accumulator if its also a dryer or the dryer pouch in the condensor tube if thats the design. New orings for everything leaking or if opened up. Replace both schrader cores with high quality viton seal designs as these frequently leak. Minimize the time that the system is open especially once the dryer element is replaced.

Pressure test with nitrogen to make sure the system is not leaking.

Evacuate the system with a vacuum pump and micron gauge to get the non-condensables (air and water) out of the system. Get down to 500 microns, blank the pump off and be sure that the system can hold that level for 5 minutes or at least only rises slightly. If it rises and holds around 1500 then you still have moisture in the system (same if it stops here on the way down). If it rises slowly up to atmospheric then you have a leak. A proper vacuum can take over an hour depending on how contaminated the system is and how good the pump is. A difficult system can get cleane faster with a triple evacuation which sweeps with nitrogen and the pulls the vacuum - three times.

Once you confirm a stable vacuum then break the vacuum with refrigerant and charge to the nameplate charge weight as a vapor through the suction side port. You will have start the system to get it all in.

Verify that the vent temp, low and high side pressures all make sense for the ambient temp and humidity. First order is to be near the green band on a vent thermometer as you approach the cabin set point and the suction line in the engine bay is sweating if warn and humid outside.

This post will bring the usual claims of overkill and "I evcuated my system with a turkey baster after I left it open for a month" or my uncle Joe never owned a vacuum pump, I just leave all the air in the system .. but again, this is what a top shelf certified shop will do. A way to save money and know its done right with good parts would be to buy the components, take it to a guy with the equipment to evacuate, you replace the parts, then back to the guy for vacuum and charge.

Good luck

 

This is great. Thank you for the advice. What you described is pretty much what I had figured out I would have to do from my other sources so this is a very nice affirmation of how to do the repair correctly.

As for leaks, I definitely have one under the middle of the compressor as evidenced by an oily residue just below the middle of it on the AC compressor bracket and on the underside of the compressor.

Since I plan to keep the Blazer for several years more, I wanted to do the repair correctly the first time so plan to replace the orifice tube/filter, accumulator, compressor and condenser along with flushing the hoses and tubes (but not the evaporator).

I'll also be borrowing the tools for the recharge and evacuation from Autozone. I already have quite a bit of experience with vacuums systems from my experience in my physics lab so this part will definitely NOT be a mystery to me. LOL

Thanks!

P.S. As far as recovery of the old refrigerant, I doubt there is any left, it having leaked out sometime last fall.

 

The most frustrating part can be the vacuum. First put new oil in the pump and check that the pump can pull under 500 microns against the first fitting, then all the hoses and gauges to the two service ports on the vehicle, then open everything up to start the process and go work on a project that takes at least an hour.

George

 

have question about AC
Here's the background. I bought the ZR2 in mid Feb. OF course the AC did not work, so I had it checked out at a shop for 130 bucks, recharged and they claim the found a leak in "a valve" and fixed it. It blew Ice cold for 2 weeks. then boom, nothing, didn't even kick on after 2 weeks. Left town for a funeral, had it checked out at another shop. They found the exact same leak in the exact same spot. Instead of tightening the valve to fix it, they replaced it. It cost a whole 6 bucks for the valve and 80 bucks for the recharge. This was last weekend. Ok in a 3 week period I've had to have this thing recharged twice. First shop claims they put dye in it to check for leaks... second shop says it's completely out of freon again but found no leaks or evidence of dye.
So far I've spent over 200 bucks at 2 different shops and still have a busted Air Conditioner system. Today it was blowing cold, but the compressor seems to be cycling very quickly. Kicks on, then off, then on and off leading me to believe it's low on freon again and leaking out somewhere else. It was blowing at 41 degrees last weekend, today it was just kinda cool, then the compressor kicked off and it started blowing hot air.

I hate dealing with AC, anyone know of any common at home leak checks?

 

 

The high pressure fitting for the guages is a very common place for refrigerant to leak. GM used a rubber ball to seal the fitting. Over 20 years the ball takes a seat and when disturbed (like when you hook up a set of guages) the seal is disturbed and in a couple of weeks, your system has little or no refrigerant left. Doorman sells a new valve with a proper Schrader valve in it.

It's going to be hard to troubleshoot this valve with dye as they always have dye on them, but if you charge your system with a can of r134a and put a drop of oil or dye on the inside of the valve, you'll probably see bubles if it's bad. Alternatively, get an electronic leak detector (sniffer type). I got one on Amazon for $20 and it works as advertised.

 

I forgot to mention a spray bottle of water with a couple of drops of liquid dish soap. Spray around everything and look for bubbles. I use this and feeling for oil more than my expensive electronic detector.