Freon keeps leaking,help needed....

yasir · 10:14 AM

every year this time i end up bringing her to the mechanic to fill her up with freon..i am now wondering as to how labor intensive it is for my mechanic to find the leak...Any schematics/diagrams that could help him find the leak..
Thanks...

turborat · turborat's Garage

Most likely the compressor is leaking. A decent AC technician should be able to find the leak in any AC system. All AC systems are basically the same regardless of car model. There are dyes that can be added to the refrigerant that can help detect the leak. If you have not converted to R134a from R12a, you may want to consider it. R134a is available off the self at about $5 a pound compared to R12a which is well above $20 a pound and requires a license to purchase.

asphaltgambler · 04-24-2006, 10:50 AM

With A/C leakage........ where there's smoke there's fire............as in where the freon is leaking out it will leave an oily residue. Most common areas are: compressor shaft/clutch hub as mentioned above, next are any fittings/joints.

Start at the compressor and look for oily residue. Then work your way down each line carefully. I'll bet you find it.

Tim Hancock · 04-24-2006, 10:58 AM

Could be anywhere, but just for yuks, you might look at your low pressure line near your right rocker as mine had a bad leak there due to the PO's poor lift pad placement at some point. I just spliced the hose and that took care of my leak. 12 months later, after installing a new drier, 134 oil and an evacuation then recharge with 134, my old SC "r12" system with a DIY 134 conversion, York compressor and all, is still blowing cold (as cold as a stock york setup can be at least)!

911pcars · 04-24-2006, 11:19 AM

My factory A/C SMEs (subject matter experts) suggest not using dyes in the system as it displaces the refrigerant volume and thus decreases efficiency. Instead, they suggest going to a shop that has an electronic sniffer - much more accurate. In addition, dye leaks iwill stain interior fabrics (clothing too). While not visible under normal light, a black light reveals all. You don't want your spouse's evening dress lit up like this.

MHO,
Sherwood

Jim Sims · 04-24-2006, 06:07 PM

In a typical 911 A/C system there are 12 hose fittings/joints, around 40 feet of hose and one shaft seal. All of these can leak or diffuse refrigerant. The flare type fittings (metal to metal seal) in the earlier systems can have problems if they were damaged due to mishandling or improperly tightened. Water in an R-12 system will combine with the refrigerant to make an acid that will corrode the system from the inside out.

The mineral oil in the R-12 systems or left over into a R-134a conversion will show a long term oily spot. The oils used with R-134a rapidly evaporate and only leave a sign if dust collected on the leak spot before the oil evaporated. Besides causing the performance loss Sherwood mentions dyes and leak stop "goo" also can cause problems/contamination with the refrigerant recycling machines in A/C shops.

Refrigerant system leak checking is best done with a chemical sniffer or an ultrasonic leak detector.

yasir · 04-25-2006, 01:11 PM

Thanks for all the responses fellas.I just made an appointment with the mechanic who is going to do the sniffer testing to find the leak.I guess the plan is if the leak is found then i am going to try refilling it with the R12a or his suggestion is to just go ahead and change the system altogether..Cost for the swap to R134...$350-$400,does it sound OK..
Thanks

911pcars · 04-25-2006, 02:00 PM

Leak-testing sounds fine.

However, if you're going to switch refrigerants; since switching over to HC134a usually entails changing the hoses and system O-rings, receiver/drier, refrig. oil, etc., I'd wait until the conversion is complete before leak testing. When they pull a vacuum on the system, any leak will be apparent. In addition, they might add a pound of refrig. and sniff for leaks.

Sherwood