Besides using the guage set go by a black light or a uv light as it's called. I think I got mine from Walmart in the sporting goods isle to spot "scorpions". And then start looking for the uv dye that should be present where it is leaking. You might even want to take out the driver's headlight and check there. I had a issues too. Found the leak around the dryer. After replacing several compressors. (Cheap junkyard ones from local u pull it place). Might even just want to order the full kit and replace everything all at once. Condenser dryer the valves compressor expansion valve. I got the kit for around 200 or so from rockauto or just look on eBay and piece by piece (make offers) at cheaper prices. Or even check Amazon for them too.