Started having air conditioner issues about 2 weeks ago. Would run sorta cool but not cold. Recharged system and put a can of compressor lube in there for good measure. Took off on a trip and had even worse problems. It started out blowing cold then went warm and stayed that way. When I switched it off for a while, it would come on cold again for a few minutes before going warm again. Today, was almost never cold. TXV? Evap? Need help - summers coming!

 

You have a refrigerant leak. Charge it with a can that has UV dye in it, then find the leak with a blacklight. A word of caution, after you put the dye in, you want to start looking for dye immediately since the compressor oil will get slung all over the place over time ..... then everything will glow under the blacklight and that-s just useless.

 

Dont just charge it without measuring pressures. It may be caused by a plugged expansion valve/orifice. In that case the high pressure will be too high, & the low will be too low. Theres a handful of conditions to cause poor cooling even when refrigerant inventoryis correct.

 

^^^^ Jim is right ..... gauges should be used ...... the symptoms and pattern described indicates a leak to me though ..... I'd bet a dollar on it.

 

Also consider that the pressure switch is both HIGH and LOW, so if the system is overcharged it will shut down the system.

But I agree with the flourescent dye & black light

 

Will hit it this weekend. Thanks for helping me out. Now to find some pressure gages.....

 

I agree you need to know the pressures to diagnose, however your symptoms are also consistent w/ evaporator freezeup, particularly if you noticed some "fog" emerging from the vents when cooling was poor. When evaporator ices, and moist air flows over the iced evaporator,fog is produced w/ higher vent temps. Also there is very little air passage through the evaporoator and air flow to vents is greatly reduced.

When you turn system off, ice melts and system will produce cold air again until re-icing. This problem is caused by failure of the evaporator temp sensor and AC control to periodically disable the compressor to prevent icing; ie compressor stays on continuously until evaporator is a solid block of ice. It can also be caused by low system charge level (part of evaporator is very cold and part where temp sensor is located is above freezing).

good luck