how to decompress a/c system

[cmz829]

I am in the middle of doing my heater core. i am at the heater core box now and i now have to decompress the a/c system to remove it. i read something before about using a screwdriver with a rag but i cant seem to find the thread anywhere. could anyone explain what i am supposed to do? i appriciate any help as i am at a buddys garage and have to have it done tomorrow.

 

[Lakebum]

You need a schrader valve tool aka valve core remover (same tool used to remove the core from a valve stem in a tire). There are two valves, one in front just to the left of the radiator cap and one at the passenger fire wall. The rag is to shield your hand and catch the oil that is mixed in with the system. THIS IS NOT ENVIRONMENTALLY FRIENDLY, but hey; gotta do what you gotta do.

 

[Shoaz]

I don't think you need to evacuate the a/c to change the heater core. That can be done without disturbing the a/c.

If you're pulling a/c parts for some other reason, then, if it's R-12, just depress the core on the Schrader valve to let the pressure out (or remove the core). R-12 is non-toxic.

If it's R-134A, the better way to do it is to take it someplace and get it evacuated.

 

[cmz829]

do you have any information about that? dont i have to disconnect the ac lines to remove the evaporator? according to the shophoenixproject guide atleast. if you know of any other way i would really appriciate it

 

[projectSHO89]

The AC lines MUST be disconnected to replace the heater core. There is no viable alternative.

Both R-12 and R134a systems have a valve similar to a tire valve. Hey, leaks happen. Neither refrigerant is particularly toxic, however, they do displace oxygen and create a risk of suffocation is the gas is in an enclosed area.

One of the greatest risks is to skin and eyes as the gas, when escaping, is super-cold and cause instant frost-bite. Gloves and safety glasses should be used to reduce risks.

Steve

 

[cmz829]

could anyone explain where the valve is at?

 

[frosho]

There are two. I think one is right in front of the battery. The other is right near the firewall on the passenger side of the engine compartment. I believe one is high pressure and one is low pressure, don't know which one's which though. They should have black plastic caps on them too.

 

[cmz829]

so do i have to relieve pressure in both? or just one

 

[Eric VerValin]

Both. I'm pretty sure.. no reason to risk it right? Good luck getting those connectors off that a/c core. I had to cut mine.. stupid tool wouldn't get in there... Good luck with the rest of the job. I just did my core a few months ago..and don't want to do it again for a longggggggggggggggg time.

And.... buy the more expensive core wherever you go, you'll thank me in a year or two.



Edit: Oh yea.. go Steelers!! $102M for Ben..

You better be a black / gold fan living in Pittsburgh!

 

[projectSHO89]

so do i have to relieve pressure in both? or just one

Either. It doesn't matter a bit.

Spray the spring-locks with PB blaster to get some of the corrosion softened.

You'll likely find that the key to getting the connector apart involves holding the spring release tool in place then twisting and turning the hose while pulling to separate them. If well corroded, just pulling won't work, you'll have to add the twisting motion. The means you'll probably have to loosen or remove hose retaining hardware as needed to allow some twisting to be done.

Steve

 

[cmz829]

i pressed the pins down to relieve the pressure and not one bit of refrigerant came out. could i be that out of r-4?

 

[projectSHO89]

Sounds like it's empty of refrigerant.

 

[93rev2sev]

All it takes is a pinhole sized leak...so yes, it could be that empty.