Need help with Sequoia aircondition

I bought a 2002 Toyota Sequoia SR5 with about 11000 miles from a Toyota dealer. The car came with a Toyota Certified Used Vehicle Inspection and warranty. Having done some work on my previous vehicles I noticed lots of bubbles in the sight-glass every time the air-condition compressor starts. As this is number 2 on the inspection list, I pointed this out to the Toyota dealer. They recharged the A/C, however, a short time later the bubbles came back. The mechanic suspected a leak and eventually replaced the condenser two months ago. Now the bubbles are back more severe and I noticed the liquid (Freon 134) pulling down and away from the sight glass when the compressor starts. I brought the car back to Toyota, but they say this is normal as per Toyota specs. This Sequoia has automatic climate control and I have to lower the setting to stay comfortable. I found out that the previous owner has also complained about the air conditioner not working properly. My question: is this normal and per Toyota specs; can there be any bubbles in the sight glass if the A/C is working proper? If not what can I / Toyota do to fix this problem before Summer gets here? Thank you in advance for helping me, Carl

Set the temperature as low as possible. Use outside air, not recirculation. Run the air conditioning and put a thermometer into the air stream in the vents. Note how much lower temperature the chilled air is than outside air...I'd like to see about a 20°F difference.

Does the compressor cycle on and off frequently? This is a sign of a low charge of refrigerant.

Stop the engine and look very closely at all parts of the air conditioning system that you can see...the compressor where the shaft comes out of the housing, the end connections of all the hoses and metal tubing, the condenser (in front of the radiator), and all other parts you can see. If you see any oil, or feel a drop of oil on your finger when you reach to touch the low out-of-sight spots, that's where the leak is. Your leak is small, so you might not see anything, or the leak may be where you can't see it.

When the system had to be recharged, there was no "suspicion" on a leak...there had to be a leak, or the charge wouldn't have leaked out.

If the compressor is short-cycling even if the air is cool, or if the air isn't cool enough, you have a leak for sure. Don't allow them to just recharge...require that they locate and fix the leak. That said, a really small leak (my Volvo takes a can of R-134a every other year) can be really hard to find. Stick with it.

Ken