Originally posted by sigprn:
Big jim why don't you tell all of us how you would find the leak. I'm just stating how my newphew would do it and he is ASE certified. As a matter of fact i kinda had same problem with my ac keep on loosing little freon. He put some special die in the system got out black light and there was a green die lighting up. He said there is the problem rite there. He fixed it and Ice cold.



Sometimes A/C leaks are easy to find and sometimes they are not. I agree the skill, training, and experience of the technician can also make a big difference. Finding A/C leaks can be one of the most challenging things a technician faces today.

Today's cars use less refrigerant than they did 20 years ago. When a leak develops, a much smaller leak will make a difference much sooner. Today's refrigerant, R134a, is a smaller molecule than the older R12. The smaller molecule is harder to contain. R134a sometimes leaks over a season just because of the rubber hose to metal tube ratio of some designs. Cars with a lot of rubber hose lose R134a through what may seem to be perfectly good hoses.

Often these smaller leaks are harder to find with the old fashion leak detectors, electronic or gas. They almost are not even used anymore exceopt on an older R12 system.

Refrigerant has oil added as a lubricant for the compressor. It is the only source of lubrication for the compressor, similar to adding oil to the fuel on a two stroke engine. Sometime a leak can be identified from the oil left behind as the refrigerant escapes. Some parts of the system don't have a very high oil content since the oil tends to gather in the low places (compressor, condensor, evaporator).

The dye that is added to help find leaks does not dye the refrigerant, it dyes the oil. If you have a leak that doesn't bring much if any oil out with it, there won't be much of any dye either.

Some leaks are temperature sensitive. The ones that leak only after the system has cooled off and the oil has settled out, will not leave any dye as a witness.

Some parts of the A/C system are not easily accessable to check for leaks from dye, or electronic leak detector. The evaporator is often hard to diagnose, especially if it only leaks from the upper part when it is cold. There are ways to help find this without tearning apart the dash, but they are not foolproof.

Maybe you can start to see more of the picture.

I have seen some exceptional technicians spend a lot of time trying to find an A/C leak that was just hard to pin down. I have seen engineering changes forced by the need to be better able to find problems. I have also seen automakers stick their head in the sand over it too. Volvo only warrants loss of refrigerant when no difinite problem can be found for 12 months. They feel that "seasonal" A/C services are customer responsibility. Later models did have less hose and more metal tubing though.

Jim Johnson 98 SVT 03 Escape Limited