Toyota Repair: 2005 Tacoma A/C Problem, electronic leak detector, routine problem

Question
Hi Ted,

I've got a 2005 Tacoma.  2.9L 4 cyl, 5 spd manual, PreRunner, Access Cab with 67K miles.  I've had all of the recommended maintenance, and the vehicle is in good running condition.

My problem is that my A/C isn't getting very cold.  This happened 2 years ago also, I took it to the dealer, they found no leaks, recharged the coolant and I was off.  Now, it's happening again.  It still gets cool, but not nearly as cold as it normally does.

I do use my A/C more than most people, so I don't know if this is a routine problem, but I've never had a car that needed a recharge twice in it's lifetime, much less in 5 years.

I've also noticed over the last year or so that when I use the A/C, I can hear what sounds like a sucking sound coming from the vents.  It starts slow, builds up in volume, and stops.  It's never louder than a relative whisper, though.  After a minute or so, it happens again.  Frankly, it's entirely possible that it's been there from day one and I just never noticed it, but thought I'd mention it just in case.

I have an appointment to take it to a dealer, but I'd like to have some info on hand before I do.  My local dealer has been less than trustworthy, and there aren't many good mechanics around for alternatives.

Thanks!

Answer
It sounds like there is a small leak in the system, when you have it at he dealer ask to have a certified master technician work on it. First they should recover all the freon and see how much comes out, if it's a lot less than the specified amount, for instance if the full amount, let's say is 1.8lbs but only 0.5 lbs is recovered, I would know there is a leak and just adding freon is just a bandaid approach, the leak should be located and fixed. The leak can be found by either using an electronic leak detector or by adding a flouresecent dye into the system then later checking it with an UV light. So much for the leak theory.
Supposing there is no leak then it's either an electrical or mechanical issue, possibly a bad  compressor clutch, clutch relay, compressor failure, clogged receiver drier or expansion vlave, most of these conditions can be checked by just connecting a/c line pressure gauges and observing the pressures when the system is active. So there you have it, it just takes someone to really know what they are doing, if the toyota dealer doesn't seem to be much help and they say "we'll just service the system" they just want to get down the road and your problem will come back later, as you know by now. You could try to find a shop the specializes in HVAC  automotive systems, don't fall for the advertised "specials" for $19.95 at he local speedy lube, good luck with this, I hope this helps and good luck.