Anyone ever swap out an A/C Compressor?
 

Hey all,

I've posted previously. I have a 95 blazer 4.3L VIN 'W'.

I've been tackling one problem at a time, and now its on the the air conditioner. It would cycle on/off every 3 seconds and blow warm air. I got a recharge R134 kit, and I was able to charge it to where the compressor stays on at idle, but shuts on/off when you give it some gas or drive it. It blows cold air as well.

All of that probably sounds like its fixed, but, the compressor sounds like... crap. It sounds like a rusty air pump or something, and it puts quite a bit of strain on the engine when it kicks on. I'd say that the compressor is pretty much shot.

I found a junkyard compressor/clutch for $100 locally, and I was wondering how involved it is to swap out the compressor? I've never done A/C work before. I have a friend that can have the R134 discharged for me the 'right' way and I could have it recharged the 'right' way after I am done, so thats not the issue I am concerned with.

I was just wondering how involved it is to get the compressor off and put on a new one. Is there anything else I should do when I do this (change seals, etc)?

Thanks in advance,
Jim

A/C compressor swap
 

Sounds like a piece of cake since you have someone to remove and replace the coolant. I'd spend the bucks for a rebuild over a salvage unit. In either case, get the clutch too.
Since the system's going to be 'open' you should replace the accumulator/dryer as a minimum (for a new or salvage compressor). I'd replace the orifice tube since it's fairly cheap. And new 'O' rings for the compressor header would be inexpensive too.

I looked at autozone and they have the compressor & clutch for $120 or so with core. Wow, pretty decent really.

I may tackle it soon, trying to decide whether its worth it or not this year, given I live in Wisconsin and its been a cold summer anyway.

It's quite easy to replace...it's right on the top, and easy to get at. That's a real decent price. You should definitely replace the accumulator and orifice tube as well...and no point putting old o-rings back on the compressor fittings.

Kudos for being responsible and having a shop evacuate/recover the refrigerant for you, I know so many guys who would just vent it into the atmosphere.

Go to your local auto parts store and get a can of oil for the a/c system. sounds like you have the hose to install it already. dump the can into the system and see if that smooths it out. worth the effort. If it's working why change it.

The R134-A I added had oil in it already actually.

It sounds horrible, and it puts a serious load on the truck. I talked to a friend and he said to me "Just get a new compressor.. The last thing you want is to blow out the compressor then the whole system gets crap in it".

Its mid-August, so I think I may actually just wait until next year at this point, but I haven't decided. I've done enough work on the thing already, but hey I have it running like a top.. Not bad for $1500 eh?

Ha Jamez70---The compressor makes a lot of noise when it runs, and it puts a big load on the engine when it cycles on. My 95 is on it's 2nd compressor and has been noisey since I put it on ( 2 years ago ). I realise that the R134 has oil in it, But when you install a dry comreessor you need to add oil in addition to the R134. a small can of the proper oil is cheap and just may prolong the drop dead date of your compressor. They are all dieing just some sooner than others. When driving along at 65mph I can feel the compressor cut in and out each time it cycles. If it's cooling run it. unless you are just chomping at the bit to dump some bucks, then change it out, But I bet the new one is just as loud.

Hello! Just wanted to give you guys a heads up in changing out the AC Compressor. There's a lot more to the AC system than just swapping parts. If you search the archives you will find a ton of info. I spent hours reading through all of it, a lot of great information on this forum.

If you pull the compressor you should change out the drier/accumulator with a new one. It has a dessicant inside that absorbs moisture in the system and if exposed to atmosphere for too long, it will absorb humidity from the air. The dessicant will absorb only so much moisture and after that, the accumulator must be replaced.

Also check the orifice tube and check the screen for debris. If there is no debris in the screen, you don't have to worry about flushing the system lines. If there is debris you need a compressor to blow out the lines and use a flushing compound. The orifice tube is inside the inlet line (lower line) leading to the evaporator. Remove the high pressure line and replace the orifice tube.

Don't forget the PAG oil for the compressor. Install the compressor on the vehicle, and add 6 ounces into the low side port on the compressor and add 2 ounces into the drier/accumulator. It's better to have too much oil rather than too little in the system. Too much oil will reduce cooling efficiency, too little oil will reduce compressor life. Connect all the lines and turn the compressor shaft by hand at least 10-20 revolutions to circulate the oil into the system lines.

Evacuating the system: You need a good vacuum pump and gauges for this. If you go to Harbor Freight you can get a 2.5cfm vacuum pump for $90. AC Manifold Gauge set is $50. Vacuum will remove residual water vapor from the system which destroys the compressor. The system must be evacuated to 29.4"Hg, (2 atmosphere's) for a minimum of one hour before recharge, the longer the better. After an hour, turn off the vacuum pump, check the gauges and let the system sit for 20 minutes to see if you have a leak in the system (you will lose vacuum pressure if you do).

Once you're sure you have an airtight system. Start the car up and turn the AC on to max cooling. Start to recharge the R134a using the low side port near the accumulator. Be sure not to overcharge the system or risk blowing the compressor. Here's a good site showing those steps....
http://www.wikihow.com/Recharge-the-...ioner-in-a-Car


Have fun!