Yes I did buy a bottle STP from Halfords & have used them several times before on other cars with perfect results so I disagree that they are rubbish, I'm not spending hundreds on it so will probably be going down the route of a leak sealer £20 a bottle, I agree that it needs a full leak test but what I don't understand is I've been using it for about 2 months & it's not lost anymore gas (maybe your right it's got a very small leak) it's running same as when I put it it, weird, thanks for your reply
Please in the name of all that is good DO NOT USE A LEAK SEALER.
Unfortunately, AC leak sealer can’t distinguish between water that’s condensed at a leak location and water that’s already in the system. It’s important to understand that a leaking AC system has already let outside air into the system and that air contains moisture. In most cases, that humidity is absorbed by the desiccant in the receiver/drier or accumulator. However if there’s any free-flowing moisture in the system, it’s usually at the orifice tube or expansion valve, since those are the areas where there’s a larger temperature drop and condensation forms. And THAT is where the problem arises. Like I said, the sealer can’t tell the difference between leak water and desiccant water. So it will react and harden WHEREVER it comes in contact with water.
Adding leak sealer to a “wet” system can cause far worse problems than the original leak. That’s why the instructions for the professional AC leak sealers require a complete system evacuation to dry out the system. Some even require a new receiver drier or accumulator to be fitted before adding the sealer. If you just add AC sealer to a wet system, don’t be surprised when it makes things far worse.
The sealer will probably work for very small pinhole leaks in the evaporator or condenser, however it is very important to remember that;
• It WILL NOT work for leaks at the compressor shaft seal or O-rings (second most common places for leaks after a holed condenser)
• It WILL clog the desiccant in the receiver drier or accumulator as the system is almost guaranteed to contain moisture if it has had a leak previously and not been evacuated and dried out thoroughly.
• It WILL reduce cooling by up to 7 TO 10%, Sealer flowing around the system will take up room within the system that refrigerant gas should take up, so you will be running without a full load of refrigerant.
• If you ever take the vehicle to a repair shop, you WILL incur large additional costs to evacuate the system because it is contaminated with sealer.
