AC change to R134A from empty
 

Hi guys,

87 ZX

I have seen others ask this, but hope to get a real straight answer.
There is no charge in my system i.e. warm air nothing close to cold coming form my AC.
In fact, since I got the car 6 years ago, I have never used the AC.

This being the case, is there anything I need to evacuate or are we rather certain nothing remains?
If I can go straight ahead and load up the R134..is there a preferred kit you recommend?

Am I correct in assuming the LOW side is right next to the Compressor and the HIGH side is at the Dryer?

Any helpful hints are appreciated.

Some things to clarify...

By "no charge", do you mean there's no system pressure? aka... the a/c system has already been opened / evacuated? If so, there was probably a leak... If the system is open to atmosphere, moisture from the air will enter the system and can cause corrosion and also kill the receiver drier beads. Also check that the compressor clutch actually spins / rotates by hand (with engine off of course)...

Check the FSM for recharge procedure... it will show you where the ports are.

As for recharging with R134a... yes it's a straight forward process as long as you do it correctly. I've done ~10 conversions from R12 to R134a. I just use the screw-on Low & High port adapters but I remove the stock R12 system Schrader valves. The system must be vacuumed to remove moisture and atmospheric air. I use the Harbor Freight manifold gauge set and their pneumatic (compressed air) vacuum pump.

Procedure:
-Remove R12 system Schrader valves.
-Replace with Low & high port adapters
-Hook up manifold gauge set to both ports
-Hook up vacuum pump & apply vacuum
-Open both low & high port knobs
-Watch pressure drop to at least -20in Hg
-Allow vacuum to continue for ~5min
-Close both knobs and watch gauges
-Pressure should hold steady. If it drops, there's a system leak that must be fixed
-After pressure test, system is ready to fill
-Remove vacuum pump & hook up first can of R134a. If system has been empty, use a can with oil / conditioner
-Purge yellow charge hose at the manifold to remove any air
-Open low knob & you will hear the R134a flow into system
-Slowly rotate can from straight up to upside down & back. This helps the gas & liquid flow more easily into the system.
-Once the flow slows, start car with a/c off.
-Turn on a/c. Compressor should kick on & continue to suck R134a into system
-An empty system will usually take 2 cans.
-When first can is empty (no longer frosty cold), close low knob, remove can, install new can, repeat purge
-Watch gauges... fully charged system low side should be at 30-40psi, high side 170-200psi depending on ambient temp (hotter = higher pressure)
-Check that the vents are now blowing ice cold air

Done.

Hey, Bravo Nismo PIck! Brilliant job, very well done. So clear! Love to see that! :006:

Hey have you thought of taking a management position at this web site? You'd be great at it! I'm definitely writing to the management for you! Cheers and thanks!

Yeah all good tips nismopick , bit you might just suck it down and see if it holds , condensers are always a weak leak point. , see if the comp clutch lock or needs regapping, not that hard to replace the hoses and you can run a solvent cleaner through the lines

Whew..OK I have never worked on AC, so a little tentative.

I have no idea what is in the AC,,i.e. it never blew cold air as I can recall. Does this automatically mean I have leak?
How else would the coolant get out? i.e where else did the R12 go? I am almost certain the compressor runs, the engine
takes on the heavier load when I hit the AC button.

Thx for the excellent instructions!