Replacing AC compressor

[zedjr10]

I got a 92 accord ex coupe and i am soon to be replacing my AC compressor. It was converted to r-134a before i bought car. So is this just a simple replacement of the compressor. It seems pretty str8t froward but wanted to ask. Am going to get a denso unit. Is there anything i need to consider that isn't in the replacement guide. Also was wondering why shops want soo much dollars for this. 420 bucks one shop wants.

[Raf99]

Simple to do, like an ALT. They charge that much because you need special tool to fill the AC with refrigerant and have to know what you are doing. I'm guessing their price was including hardware too (the AC compressor).

[Fleetw00d]

I just cost me $142 for an evacuate and recharge (with about 45 minutes in between so I could go home and replace the pressure switch). I believe it is technically illegal to deliberately release the Freon to the atmosphere, so the system should be evacuated prior to changing the compressor (unless it has all leaked out already).

[F22Chris]

You NEED to replace the expansion valve & drier as well when replacing compressors. Get ester oil, and fill refrigerant to .7 of the factory r12 capacity if using 134.

[zedjr10]

Simple to do, like an ALT. They charge that much because you need special tool to fill the AC with refrigerant and have to know what you are doing. I'm guessing their price was including hardware too (the AC compressor).

it was 620 including compressor. What special tool? DO you mean the same one i recharge it with? If not can i get a loaner from parts store?

[zedjr10]

You NEED to replace the expansion valve & drier as well when replacing compressors. Get ester oil, and fill refrigerant to .7 of the factory r12 capacity if using 134.

I don't see that in the replacement guide. Where would i find a guide on that?

[Raf99]

No guides around that I am aware of but he's right. You need to eliminate the old contaminated stuff. I've seen people not do it but it's not the proper way to do it. What i was talking about was the compressor, gauges, and know-how to fill the system with refrigerant. Only a certified technician should do it.

But still sounds like you need to shop around for a lower price.

[zedjr10]

No guides around that I am aware of but he's right. You need to eliminate the old contaminated stuff. I've seen people not do it but it's not the proper way to do it. What i was talking about was the compressor, gauges, and know-how to fill the system with refrigerant. Only a certified technician should do it.

But still sounds like you need to shop around for a lower price.

Am going to do it myself. It can't be that hard to fill system and anything other to do. I don't trust mechanics anymore at all. It is not like they go to special refrigerant school for 4 months or something. They was probably shown how to do it by a workmate. The coolant in the system now is at 0 psi on low side port(all leaked out). I'll try to find some guides for this on youtube.

[zedjr10]

I just cost me $142 for an evacuate and recharge (with about 45 minutes in between so I could go home and replace the pressure switch). I believe it is technically illegal to deliberately release the Freon to the atmosphere, so the system should be evacuated prior to changing the compressor (unless it has all leaked out already).

It is also technically illegal to drive 56 in a 55 and cross the street in an unmarked crosswalk.

[Raf99]

I knew a guy who did it for big rigs, and he did my car once and explained it to me. As technical as I am he confused the heck out of me in regards to low and high pressures, and what to look for, etc. You also need a proper AC filling machine which can vacuum the lines out first to create a low pressure, remove moisture (which is why you need to replace the drier), then introduce the AC refrigerant to it. A skilled tech can also tell you why it may not work if something goes wrong (drier, evaporator, leak detection, or other). There's a lot that goes into it especially when your AC works but is not cold. It's not as simple as "filling something". Also when changing the AC unit you may introduce moisture to the system which is bad.

Take a look at this page. If any of it confuses you best to stay away.
http://www.instructables.com/id/How-...r-Conditioner/

[F22Chris]

You need a vacuum pump, thermometer, and a gauge set minimum. System pressure is relative to ambient temperature. Higher temps = higher system pressure. Say it’s 100 degrees outside, that high pressure line can reach 300psi.

Gauge readings tell you what could be a potential problem within the system.

If both low and high readings are too high, you’ve over charged the system.

Too low of readings on low/high usually means there is a slow leak, or the system needs a charge.

A lower low with a higher high means there’s a blockage - which in our case is the expansion valve.

A high low side with a low high side points to compressor failure.

If you’re hell bent on doing it yourself, the cost of a pump/gauge set is already just as expensive as getting it done at a shop. That being said, you can do it.

1.Evacuate the system. Legally obviously. Don’t be a scumbag.

2.Hook up the vacuum pump to remove all moisture and determine if you have a leak or not. System should hold 30inHG - in your case it won’t right?

3.Do your repairs. Compressor, expansion valve, drier, o-rings.

4.Confirm your repair is good. Put vacuum on system to see if it holds.

5.Add ester oil to factory specs. You can do this with your gauge set using the middle line. Just measure the amount of oil needed, and use the vacuum within the system to suck up the oil. 1990-1992 need 4oz of oil where 1993 models need 4.5oz.

6.Charge with r134 to 0.7 of factory specs. In the CB7, 1990-1992 need 32oz of r12 which means 22.4oz of r134. 1993 models need 30oz of r12 which means 21oz of r134.

If everything is good, start the car and let the AC run on high for about 5 minutes to regulate with your thermometer in the vent. Functional systems should put out 45* or colder air.

[zedjr10]

You need a vacuum pump, thermometer, and a gauge set minimum. System pressure is relative to ambient temperature. Higher temps = higher system pressure. Say it’s 100 degrees outside, that high pressure line can reach 300psi.

Gauge readings tell you what could be a potential problem within the system.

If both low and high readings are too high, you’ve over charged the system.

Too low of readings on low/high usually means there is a slow leak, or the system needs a charge.

A lower low with a higher high means there’s a blockage - which in our case is the expansion valve.

A high low side with a low high side points to compressor failure.

If you’re hell bent on doing it yourself, the cost of a pump/gauge set is already just as expensive as getting it done at a shop. That being said, you can do it.

1.Evacuate the system. Legally obviously. Don’t be a scumbag.

2.Hook up the vacuum pump to remove all moisture and determine if you have a leak or not. System should hold 30inHG - in your case it won’t right?

3.Do your repairs. Compressor, expansion valve, drier, o-rings.

4.Confirm your repair is good. Put vacuum on system to see if it holds.

5.Add ester oil to factory specs. You can do this with your gauge set using the middle line. Just measure the amount of oil needed, and use the vacuum within the system to suck up the oil. 1990-1992 need 4oz of oil where 1993 models need 4.5oz.

6.Charge with r134 to 0.7 of factory specs. In the CB7, 1990-1992 need 32oz of r12 which means 22.4oz of r134. 1993 models need 30oz of r12 which means 21oz of r134.

If everything is good, start the car and let the AC run on high for about 5 minutes to regulate with your thermometer in the vent. Functional systems should put out 45* or colder air.

AM not hell bent on doing it myself, i just want to do it cause mechanics suck but and whatever they know or do isn't all that difficult. It isn't rocket science. Elon musk learned rocket science in 6 months. I can learn AC systems am sure in a few days if i had to which i don't really. I just need to follow some laid out procedures. First thing is find all my leaks using uv dye. I know the compressor is leaking but what else. I am not going to buy the manifold gauges or pump. AUtozone loans them out. I've seen that i should also replace the receiver/drier and any o-rings. I didn't know i should replace the expansion valve. Is this really necessary?

[Rilas]

Just an FYI even if you rent the manifold gauges, I don't know if you can rent the vacuum pump, and you need an air compressor to run both. Even if you just borrow a pancake air compressor. That's what I've had to do the last few times until I bought my own compressor.

[zedjr10]

Just an FYI even if you rent the manifold gauges, I don't know if you can rent the vacuum pump, and you need an air compressor to run both. Even if you just borrow a pancake air compressor. That's what I've had to do the last few times until I bought my own compressor.

Ok good to know. I will have to find a parts store that loans out a compressor hopefully. I have a question. My denso unit is 471-1186 which says it is for R12 freon. Does this matter at all? My system has already been converted to r134a.

[F22Chris]

AM not hell bent on doing it myself, i just want to do it cause mechanics suck but and whatever they know or do isn't all that difficult. It isn't rocket science. Elon musk learned rocket science in 6 months. I can learn AC systems am sure in a few days if i had to which i don't really. I just need to follow some laid out procedures. First thing is find all my leaks using uv dye. I know the compressor is leaking but what else. I am not going to buy the manifold gauges or pump. AUtozone loans them out. I've seen that i should also replace the receiver/drier and any o-rings. I didn't know i should replace the expansion valve. Is this really necessary?

I’m slightly butt hurt because I’m a tech, and would like to think I don’t suck butt. Which makes me wonder.. If it’s so easy why are you asking? There’s trade school for this, so no. Odds are one can’t learn it in a few days.

Charge the system with dye/freon before you evaluate the system - let it run & leak so you can detect the dye. Then just follow the steps I gave and you’ll have working A.C.

The r12 thing doesn’t matter. But the amount of 134 you add will not be the same like previously stated.

Yes you need to replace the expansion valve. I wouldn’t suggest it if it wasn’t needed.

Ive literally given you most of the info you should need. Conversions, oil amounts, etc. The only thing I can’t give you is system pressures because I don’t know what the temperature is going to be whenever you decide to do this.

And if you can’t figure out how to replace an expansion valve, idk what to tell you as my last post was the biggest spoon feed I’ve ever done.