a/c recharge questions 99 3.4

I hadn't driven much and noticed yesterday the ac is not working...so don't know how fast it happened.

I have some gauges and can borrow a pump from autozone. The gauges I have do not have a bleed option for middle (yellow) line.

Wondering if I can vacuum the the system and (if it holds pressure) disconnect the gauges and fill with a handheld can with an inline gauge. I understand these are not as accurate.
Also is it advisable to add oil and ho does one calculate that?

edit...I just hooked up the gauges and low side was 45, high side ~50. The compressor is turning. There was freon the the high side gauge hose when I disconnected it.

 

Yes
On my last ac job(Subaru)
Found that expansion valve failing
(Would blow ice cold, then hot for 20mins then back to ice cold)
Installed new EV and new O rings on hoses
Vacuumed system and pressure held
Added no oil
Then re-charged system (with assistance from neighbor with gauges)

IMO
Unless RR’ng a specific “larger” part(dryer/condenser/compressor) no need to add oil

funny, then 2 weeks later my other subie’s compressor went out
Now then I started to look up just how much oil to add for compressor/dryer
Turned out both OE parts pressurized in parts box with oil. So then just vacuumed/confirmed held pressure/recharged

unk if Toyota ac parts come with oil thou

 

You do not need to pull a vacuum to add refrigerant to your system. You would only need to pull a vaccum if you completely lost a charge and or repaired a leak after it was open to atmosphere. If your just low on refrigerant, I would charge it with straight 134a mixed with yellow dye. Bleed the air out of the service hose before opening the valve and do not use refrigerant with any form of leak sealant. Then find your leak with a UV flashlight, recover the refrigerant, fix the leak, pull a vaccum and recharge the system. You can take your time fixing it if it turns out to be a very slow leak.

 

Also, you do not need to add oil unless you end up replacing major components.

 

>>if you completely lost a charge
can you clarify if this includes blowing ambient temperature air? ie low or missing R134? thx

edit...I just hooked up the gauges and low side was 45, high side ~50. The compressor is turning. There was freon the the high side gauge hose when I disconnected it.

 

Completely loosing a charge means that you lost all of your refrigerant and no longer have a vaccum. 45psi on the low side does not sound like you are low on refrigerant so you may have another problem. You don't want to overcharge the system and add to your problems. Diagnosing AC issues beyond basic refrigerant leaks does take things to another level but there are some great videos out there if you really to DIY.

 

Is the compressor clutch actually engaging or are you just seeing the pulley turning? Your rpms will drop when the clutch engages.

 

Yep, and too much oil is not good.

 

>>Your rpms will drop when the clutch engages.
At idle the rpms rise 200-250 when I turn on ac.

 

Well, not freon, but I am being a jerk. I agree with Sparky, verify that the clutch is actually engaged and turning the compressor.

 

The 'idle up' sounds like it's working but that doesn't mean the clutch is engaging.

 

I went through something *similar* enough you can read through some of this if it helps, though will it? idk.

https://www.tacomaworld.com/threads/fsm-spec-for-5vz-ac.833564/#post-29868785

https://www.tacomaworld.com/threads/recharging-ac-after-leak.833787/#post-29875708

https://www.tacomaworld.com/threads/no-power-to-ac-compressor.836317/#post-29953787

 

Exactly. @edbranch , can you test voltage? Do you have 12V at the compressor clutch when it's calling for cooling?

 

I have a multimeter...can check if I can get to the plug tomorrow. thx.

edit: I am remembering that several years ago the mechanic that did the timing belt. broke the ac terminal and I had to go to another shop to get it soldered. It is difficult for me to get to...

 

Yes, definitely check that solder connection. Hopefully it's that simple and can be repaired.