Taco, thanks for the explanation of the ac system. when i took the truck to have the system emptied, the fellow told me he only got 2 oz of freon from the system. he suggested i may have a slow leak. when i removed the compressor, there was no oil in it. replaced the compressor but had to use an old o ring as one of the o rings shipped was too big. 1st concern.
was going to replace the drier but now that there may be a leak, i may just replace the condenser. i think i may be in over my head.
This is sounding more and more like the problem you are having is just a slow leaking system over the past 10 yrs. All automotive systems begin to leak from day one and there is a known average leak rate. With 2 oz. of refrig. remaining on an '06 you are likely in that expected mean. By comparison, the system starts with only approx. Edit: 22.1-22.22 oz
Drier: remember, you have no way if knowing if the drier is bad because it is an integral part of the condenser only. I do not consider the condenser a big deal to replace and it only has two O rings. But don't throw money at the condenser yet but read on. Oh, and speaking of O rings, I am a big fan of the OEM O rings and would never consider putting back a used or improper size ring.
Oil in Compressor: not surprised that you did not find much oil in the compressor. You will find oil throughout the system as it moves with the refrigerant and collects in the various low points when the system runs. If you still have the old compressor measure how much oil was in there if you can.
All the oil in the AC system comes from the compressor at the time of manufacture. No additional oil is added during charging. A new compressor has 150ml (approx. 5.3 oz.) of oil in it. On the assembly line the compressor with its oil it is bolted in, the entire system charged with refrig, and then operated. That 150ml is is distributed to all the internal parts before some makes it back to the compressor where only about 2-3 oz. or so resides. That is why you want to invert the old one and drain it to measure the amount as you would otherwise be adding another 150ml of oil from a new compressor and most of the time you will have to remove oil from the new compressor.
This is important because the oil takes up space in the system that could otherwise be used for refrigerant and excess oil drives the system pressures up often way too high That's a no-no.
The biggest thing you need to do at this point is make sure the system is not open, and remains open for only short periods during work, because moisture in the air enters the system and contaminates it and it will all need to be evacuated under vacuum prior to recharge.
For 2006 I would just assume that every O ring needs to be replaced.
If this were mine I would not just start throwing parts at it because the AC system can drive one to the poor house real fast. Here is what I would do:
1. Go to a real automotive AC shop and have them leak test the system with whatever technique they like using.
2. Assess where the leaks are. O rings are cheap, bigger parts are not.
3. If it appears as though it is just misc. O rings leaking, buy and use the OEM O rings only. I would be happy to give you the part numbers and location of where an O ring is located on the system
4. Before replacing O rings and recharging the system you need to remove the compressor, and determine how much oil is in it. Report back and I will tell you how much oil resides in the other stuff so you do not overfill. Make sure you state if any hard parts were replaced so that the oil in them can be accounted for.
5. Replace the O rings, evacuate the system using a deep vacuum, and then recharge.
6. Have it recharged with R134A putting the exact
amount in, by weight and weight alone. The amount to put in is located on the sticker under the hood and is usually near the top of the radiator. Do not recharge on the basis of system pressures per the AC gauges as those should only be used for diagnostics on Tacoma systems IMHO. Do not give it an extra amount "for good measure" as a slighly overcharged or slightly undercharged system on the Taco behaves much the same way -- it does not cool very well if at all.