Replacing A/C Compressor (depressurizing system?)

[winston856]

Hello everyone, I'm going to be replacing my A/C compressor in my '07 Sedan and I had a question or two.

First a little backstory: The compressor has not functioned in at least 3 years now (likely more). The system was diagnosed by toyota because it wasn't functioning and they came to the conclusion that the compressor was the issue.

I'm planning to purchase a new (re-manufactured) unit off rockauto.com and just replace it myself to save on cost (toyota wants around 2k for parts/labor).

I was just going to dive in but I'm worried about pressure in the system. I've wrenched on cars plenty of times but never with the HVAC system.

Is there worry of Freon escaping forcefully when I disconnect the hoses from the compressor? I don't know how or even if I need to depressurize the system. I see that term referenced but never heard how to properly do that? That's really my only question, I know about matching the oil level in the new compressor to the level the one in there currently has.

Can anyone offer some tips, knowledge or advise me on this procedure? It's much appreciated!

[TOLMACH]

I would check the repair manual first (Sorry can not help more)

[CTScott]

If the system is pressurized you want to bring it to a shop that can collect the Freon (as it is illegal to vent it to the air). Once it is purged, you can disassemble it without issue.

I own a vacuum pump and manifold gauge set, so do my own AC work. With my manifold, I can connect a tank to capture the exiting Freon for proper disposal, if I am working on a pressurized system.

[Geoff Peace]

Originally Posted by CTScott

If the system is pressurized you want to bring it to a shop that can collect the Freon (as it is illegal to vent it to the air). Once it is purged, you can disassemble it without issue.

I own a vacuum pump and manifold gauge set, so do my own AC work. With my manifold, I can connect a tank to capture the exiting Freon for proper disposal, if I am working on a pressurized system.

Interesting! Here in the UK it is also illegal to discharge refrigerant AC gas to the atmosphere. It has to be removed, weighed, a form filled in. After testing the system, (compulsory), The new charge also has to be weighed, the system filled, another form filled in. The price of recharging would be greatly reduced if there was not so much form filling.
Regards Geoff Peace.

[winston856]

Originally Posted by CTScott

If the system is pressurized you want to bring it to a shop that can collect the Freon (as it is illegal to vent it to the air). Once it is purged, you can disassemble it without issue.

I own a vacuum pump and manifold gauge set, so do my own AC work. With my manifold, I can connect a tank to capture the exiting Freon for proper disposal, if I am working on a pressurized system.

I just wonder if the system is still pressurized after 4+ years of non use. I didn't want to start disassembling it and get sprayed, don't know if that would even happen

[CTScott]

Originally Posted by winston856

I just wonder if the system is still pressurized after 4+ years of non use. I didn't want to start disassembling it and get sprayed, don't know if that would even happen

You can verify that by turning AC on and looking a the sight glass on the aluminum tubing. If you don't see any bubbles, then it is likely empty.

To verify that before disconnecting the tubing, you can remove the cover from the valve on the low pressure line (the larger diameter tubing) and pressing the center of the valve for a split second. If nothing comes out it is empty.

[winston856]

Originally Posted by CTScott

You can verify that by turning AC on and looking a the sight glass on the aluminum tubing. If you don't see any bubbles, then it is likely empty.

To verify that before disconnecting the tubing, you can remove the cover from the valve on the low pressure line (the larger diameter tubing) and pressing the center of the valve for a split second. If nothing comes out it is empty.

I guess I'll have to check the low pressure line considering the compressor doesn't even kick on at this point. The green light turns on when the A/C button is depressed but no compressor.

Where is that valve you speak of located? Easy to get to?

[CTScott]

Originally Posted by winston856

I guess I'll have to check the low pressure line considering the compressor doesn't even kick on at this point. The green light turns on when the A/C button is depressed but no compressor.

Where is that valve you speak of located? Easy to get to?

It's easy to get at. It is located on the car's right side under the hood. Unscrew the grey cover and you'll see the valve:

AC LP Valve.jpg