mmatheny

I did this on my Taco, but applies to all vehicles. AC was weak, so I thought I'd go easy, bought one of those Freon cans with the gauge on it, dialed in the OAT, and pushed Freon into it until it registered correctly on the low side. AC was COLD! BUT while idling in extreme heat, started short-cycling. So I put my regular gauges on it. The HIGH side was WAY high, even though the LOW side was in the range. I found that lowering the LOW side about 2 PSI lowered the HIGH side by over 10 PSI!!


So lesson here is don't go easy. Use a FULL GAUGE SET!! Once I lowered the LOW to still be in the range for the OAT, the HIGH side came into spec also. AC was still very COLD and no short-cycling!!


Did same on my wife's ES300 after the Taco - and it spits out ice cubes!

Oro

Were you doing the gauge reading at idle? The specs are supposed to be at around 1200 to 1500 IIRC, with air flow over the fins (fan on). That is usually the difference between reading correctly (on the gauge) at idle but too high at proper RPM.

I serviced our ES300s a/c last month and also found it was very sensitive to low side pressure, and would short-cycle if too far above the min. spec'd for the OAT if at idle. Making the reading at ~1,200 rpm made it all look good.

NotADood

Lexus Master Tech here,

Newer Toyota (Denso) A/C compessors are much more efficient than older ones (2007ish +) high side pressures such run around 200 psi on a hot day at idle, but low side can run as low as 17psi. If you are buying the cans from an auto parts store, the "green" zone is usually in the 30 psi range for the low side becuase that's what the older compressors run at. If you fill it to 30 psi for the low side, the vehicle is drastically overfilled, and the vehicle will not cool very well.

mmatheny

I was running 1500 RPM, fan full, recirculate, all doors and windows open. About 85° outside.

mmatheny

OK - so what's the charge pressures for this car?? I have googled and all I can find is HOW MUCH Freon to put in, not what the charge pressures should be!

mmatheny

Does anyone have a manual they can look up the AC pressures for me please?

mmatheny

I just got a generic pressure chart. Will that work for this vehicle?