Mastercool 55900 Refrigerant Leak Detector, Blue

Like the equipment and is very sensitive.

This little guy solved a very frustrating issue I was having with my '07 C6 Corvette. For 3 years straight I would have to deal with a VERY slow refrigerant leak that would leave me with no AC each Spring when I would fire it up the first time after the long winter indoors. I changed so many parts and added dye, of course, but still no joy. I finally broke down and bought this tool when a local shop scared me with a big fat bid for digging into the issue. It turned out that there was a pin-hole in the condenser that could not be viewed by line of site with or without little mirrors and an IR light. I slipped this sneaky little sniffer-wand up in there and it started beeping like crazy. Bam! I installed the new condenser the next day and it has been hold perfectly with ice cold air at 45 degrees. My corvette is now colder than my wife... but in a good way :) I recommend this tool to anyone who wants to get to the leak quickly. It will pay for itself the first time you use it and if your friend's AC has an issue you might get to be someone's hero. Giddy-up.

solid tool 3 stars for now have to use it more to make sure the quality is there will update

Great product,does its job flawlessly

I used to use a Harbor Freight detector before this for R-134a vehicle applications. Those inexpensive detectors from HF, and other imports here on Amazon can work to a degree, but when it came time for a replacement I did the research and selected this Mastercool 55900. The 55900 has proven to be superior overall to the more entry level tools. User interface wise you can both control the volume and mute the tones. The self test LEDs, sensitivity LEDs, and detection LEDs are all green in color and of high brightness so you can easily see them in sunlight. You can control the degree of sensor sensitivity via the touch pad controls as well. Features wise the tool comes in a rugged shop grade storage case, and includes two Energizer C batteries (I recommend you always store the tool with the batteries removed to prevent damage to the tool from them leaking if you are not using the tool regularly). Easy to read and understand instructions are included in hard copy, as well as via a PDF on the Mastercool website. Mastercool includes a small glass vial of a test gas that you can use to check that the tool remains functional and in calibration. A very professional and high quality touch. However, I only gave this tool 4 starts out of 5 because I found it often required multiple passes to confirm the location of very small R-134a leaks, and with the sensor housing in nearly direct contact to the hose or pipe itself. These are leaks I would not expect lower cost tools to detect at all, and so the rating is less a reflection on the 55900 and more on the abilities of electronic detectors in general. I only use them as a last resort when R-134a dye injection is not an option.

Does not perform as advertised. Not accurate. Does not provide repeatable results. Absolutely will not work with any amount of air moving across the tip, such as from HVAC vents in a vehicle. Constantly freaks out and goes into “interference” mode. Sent it back to the manufacturer to be repaired and it came back working the same.