Reddit reviews FJC 6036 R134a U-Charge Hose with Gauge

Yes, that sounds like you need to recharge. You can do it pretty cheaply with a recharge kit like this one or get a cheap set of charge hoses.

However, if you have a leak, that'll need to be fixed or you'll just be doing this over and over. I normally do a charge, and if it doesn't stay, get the system serviced.

Check the water that drips from your AC for Dye. If that's got dye, that'd def your evap core.

There are refrigerant detectors (see /u/Vistandsforvicious 's post). You turn the AC on, and it can detect very small refrigerant leaks. Most AC shops should have one. They look like this And basically sniff to find very small leaks. Beeping when stuck into your vents when the AC is running means your evap core is leaking, no beep... no leak. I'd suggest getting a professional to do it, not the crappy one I linked. Or you can roll the dice and use the el-cheap-o from amazon.

edit: But if it's a leak, you should be able to do it with 0 guesswork involved. It just takes a lot of persistance. Use a q-tip to clean up that spot of oil on the back of the compressor, and see if recharging it makes the oil spot come back.

PS: If you're adding refrigerant, do not use the crap with leakstop. Use something like this with the white cans of only-refrigerant to fill your AC. If you're refilling it yourself, I wrote a long post on how to do it mostly-correctly.

Here ya go...

Supco BPV31 Bullet Piercing Valve https://www.amazon.com/dp/B00DM8J3MI/ref=cm_sw_r_cp_apa_7tu3AbWW31RXF

InterDynamics RLS-134 13oz. Refrigerant R134a with Leak Sealer https://www.amazon.com/dp/B000COD8R6/ref=cm_sw_r_cp_apa_Kuu3Ab8SRPRGN

FJC 6036 R134a U-Charge Hose with Gauge https://www.amazon.com/dp/B00620PXMW/ref=cm_sw_r_cp_apa_bvu3Ab2FH7N4M

R12 R22 R502 Screw to R134A Fast Conversion Adapter Valve 1/4'' to 8v1 Thread https://www.amazon.com/dp/B01HL55KBU/ref=cm_sw_r_cp_apa_Wvu3AbSJXAZ8H