tsl95

2005 RX330

Since we're now in warmer weather, I have noticed the A/C has a problem. It starts out being really cold and if you drive for more than 10 min or so it seems to lose the coolness and get a little warmer. A few minutes later it will be cold again. I added R-134a to the system and noticed no difference.

Also, the two fans behind the radiator come on after driving 15 min or so. They get really loud and seem to only come on when I slow down and come to a stop (sometimes come on while I'm driving if I'm on a drive of about 30 mile or more). The coolant/anti-freeze level was very low so I added some to the normal level, but still no difference.

Not sure what else to try before taking it to a mechanic.

mdbrown

Just adding refrigerant without knowing how much is in the system can make it perform worse. If the system is low it's possible for the evaporator to freeze up which will cause it to blow warmer until it thaws. The fans may have a separate issue, if they are noisier than they used to be they could be failing but I don't believe the two issues are related. Typically when the fan begins to fail the A/C will work fine till you stop moving and work again when you start moving again. Before you do anything else you need to get some gauges on your A/C system and see what kind of pressures you are getting.

05RX330AWD

A possibility could be that you still have air in the cooling system, you need to burp the air out of the radiator & cooling system while the RX is running, fill until full to capacity with no visible bubbles.
Careful with adding refrigerant, at times there can be issues on the High end of the A/C system which will not be tested for the PSI value with a DIY R134a kit.

tsl95

Another thing I noticed is a liquid swooshing noise occasionally. Like some liquid is moving around.

BlackLexRX

Check your passenger floorboard carefully for wetness from AC condensate leaks. Part of the AC system is there. If no leak there then good, and it may not be related to the problems you're having. However some here have had AC problems which can manifest themselves as leaks into the cabin which require carpet removal and even replacement. Search forums for AC problems. Sometimes it can be as simple as purging the lines with weed whacker string from under car and/or passenger footwell.