ComStar A/C Zero-Leak, Permanent "Stop Leak" for A/C Systems, Seals Leaks Instantly, Non-Hardening, Polymer-Free, Eco-Friendly, Made in USA, 4 Ounces (90-700)

This worked great for me to plug a leaky fitting that connected a rubber elbow to an aluminum hard line. I was dreading having to evacuate the freon, introduce a sealer, then pull a vacuum and repush freon and a little compressor oil. (I could see that some compressor oil was lost in the engine bay.)I bought a $35 pressure oil and dye injector kit here on Amazon and put two ounces of this into my system with it, which enabled me to seal and re-oil all in one shot. Basically the sealant is blended into a PAG oil base. So far so good, and I saved myself a lot of DIY time or costly labor on an 18-year-old car that I plan to get rid of in two years anyway.I've used a couple of the other "quick-shot" tube kits that you can connect to your refrigerant line and push with the refrigerant top-up. That stuff has a different formulation and is just not enough volume to plug more significant leaks. This requires more work and equipment (pressure oil injector) on a charged system, but the results are superior.I'm a believer in this stuff, and I'll be using it from now on on my older cars, refrigerators and home a/c systems as there is little to lose at that point if it doesn't work. I just had my two home evaporator coils replaced at a "steal" price of $3,600, and I wish I had seen this first!

I have a Hyundai H100 van (Hyundai Starex here in the Philippines) whose aircon system was losing charge after two months. After two cycles of refrigerant recharging, I stumbled into Comstar Leak Sealer here in Amazon, read all the positive reviews, researched on the sealer technology, bought two bottles and had those shipped to the Philippines. It also helps that Comstar is considered as non-hazardous/non-flammable/non-toxic material so I did not have any issue on airfreight shipping.I injected the contents of one bottle myself into the low pressure port using an oil injector driven by the high pressure port (tools used: oil injector and manifold gauges). I am very happy with the results - no more leaks and my Hyundai van's aircon is cold, something of a necessity in a tropical country where I live.This stuff works! No clogging of expansion valve or filter drier core. And more importantly, the remaining Comstar leak sealer now acts as a preventive leak sealer as any incipient future leak will immediately be sealed early, thus preventing the loss of refrigerant charge.

So I am a home mechanic. And that means I save money. When you save money you can afford to spend a little to save a lot and that is what I did. 2009 Toyota Avalon started to leak at 200,000 miles. I would put in a partial can about once every 6 month and then a month and then a week. Each time doing what I did car after car before.Finally I bought a vacuum pump and gauges. I got a deal locally and see even a better deal on Amazon for a combo at about $119.00, get it and be happy. I am not a pro and I do or did not need a mega expensive system.I bought this stop leak and some dye along with a detector light and glasses (glasses useless) turned out after this goo stop stuff those glasses and dye were not needed since there was no leak after.Anyway stick with me here because the following is important.I put the A/C Zero leak into the yellow tube from the gauge manifold. It does not mater from which side just keep both sides up to keep it in and then connect the can and hose back up in a mater that keeps it in the tube. Yes it is messy. What is IMPORTANT is this. "Once the can is opened and freon has gone into your system and enough freon is in to start the A/C pump and another can or partial is put in to get the Gauges at Low side 30PSI and high side at 145PSI or a little less for my car. Keep the car running.Did you catch the last part KEEP THE CAR RUNNING. That pump in your A/C system likely flows very very slow and it has many feet of tubing...what maybe 100 feet when you figure the side to side to side in the evaporator and condenser and then the dryer and the delivery and return tubes. My point is leave it running for an hour or two so the leak stuff can get in the entire system and find the leak. Even if it is cold outside , leave the A/C on with the heat. A/C draws moisture out of your car and the pump can circulate that even when the heat is on. That is how the defrost works you know. DRY AIR blowing heat using the A/C and the heater core at the same time. Anyway. My A/C is ice cold and hanging in there. I expect to put the other half of the A/C Zero-Leak in if needed and will update if I do. I planned to pay $2000 for a new A/C if this did not work because it is cheaper than a new car , also the Avalon is a sweet fast riding car and it is paid for. Good luck for your first try"

...have not noticed any issues as of yet. Need to complete a vacuum test to verify effectiveness.

Unfortunately didn't work for me. And it appears this brand doesn't offer a money back guarantee like other stop leak products. I would recommend buying another product, based on it doesn't work... And they don't stand behind their product.

had a leak in my evaporator ,put this stuff in and it stopped my leak ,have cold air for the last 3 months,those sealer can dont work ,this stuf does work

Used half the bottle, but still have the Freon leak. Gave it three stars because the leak may be in the evaporator coil and may be too large to seal. This may work on small leaks.It is difficult to get into the system as I had to push the Schrader pin down while slowly dripping this into the valve.Probably worth a first try to seal leaks, but need a better way to get into the system.