QuestionI have a 2005 Kia Sedona mini van that is losing freon. I have had it charged twice and in less than 24 hours it lost all freon. Mechanic has said it is losing freon on the high side. He has used pressure test, sniffer and cannot find the leak. he has also used about 7 ounces of dye. I am taking it back to him today. Any direction would be great. He has checked everything in the rear as well.
AnswerKevin,
There is nothing more frustrating than AC leaks but you don't have a small leak. You have a massive leak that should be pretty easy to find. (easy for me to say, I am hiding behind this keyboard)
First off, no more dye. You already have too much in the system. If you over oil the system you are going to end up with a compressor problem if the compressor is mounted low. Not quite sure how he knows its the high side but doesn't know where. High side is Compressor, lines and condenser (and a few more doodads). Most of the high side is very accessible and dye will quickly exude from the operating pressure and temperatures
Strategies for finding those tough to find leaks (every tech is different but here are some tricks I use)
1. Nitrogen. Love that nitrogen! I charge a system to 200psi of nitrogen and then go over it with an ultrasonic leak detector or just plain soap and water with a weed sprayer. You can hear the smallest of leaks from 2 feet away just like rice crispies or bacon frying. It has to be the most undervalued leak test equipment out there. Most shops will already have nitrogen for filling tires. Its an inert gas, dry and can safely bee handled and purged to the atmosphere when done. We already have 80 percetn per volume around us, why not a little more? Only problem is a good sonic detector is 500.00. But you can hear a leaking tire from 50'!
2. Tricks to find evaporator leaks. Run the heat on high for 5 min, shut van off and plug evaporator drain tube with a plastic body plug. This will cause the evaporator to expand a bit as its made of aluminum. Without the air on the pressure will be higher and it will leak if its leaking. refrigerant is heavier than air so it will build near the drain tube and when you pull out the plug the tester will go off.
3 Cover vehicle with a tarp when looking for leaks. I know it sounds crazy but forensically speaking a black polyurethane pool tarp works great. If you remove all ambient light from the spectrum and use just the UV light for leak testing (accentuated with yellow glasses) you really can't miss the leaks.
Two charges in 24 hours is a massive leak. That's 3 ounces an hour for your vehicle based on the recommended charge!! It should be very easy to find with these methods. I suspect it may be in the low side if he can't easily find it as the low side components are typically harder to find and spot without dis assembly. I also use a Snap-on Boroscope with a UV head attachment and drill holes in HVAC boxes that I have to when I do. Sometimes the leaks I can't find are the ones I don't WANT to find if you know what I mean. I hate replacing Evaporators. Expensive and time consuming and hard on the back. And I am lazy as well.
I can't tell you where it is leaking but I think your technician needs to change his leak detection strategy.
HOpe this was helpful!
Wayne
