Saratoga

I have a 2009 Civic with 135k miles. Last year the AC was blowing cool air, not cold air as it did the prior year. I did not have time to investigate. This year it is blowing hot air. To me this sounds like a leak, may be a slow one. A visual inspection, without using dye and a UV light, did not uncover any obvious leaks. I am considering drawing a vacuum and recharging with a refrigerant that has a dye. If I find a leak fix it. If I cannot find the leak and the air is cold, then call it fixed, for now. Does this sound reasonable? Should I replace the receiver/dryer desiccant prior to doing this?

ezone

Run the engine, turn on the AC.

Do the radiator fans turn on?
Does the compressor clutch click on and spin?

Saratoga

Yes, both radiator fans were on and the compressor clutch spins. I felt the high pressure line and the low pressure line near the fill/blead valves and they were slightly warm to the touch. I felt the discharge line from the compressor to the condenser and it was very warm to the touch. What does this tell me?

ezone

Fans run, compressor runs, system still has a partial charge.
Suction line not cold, probably somewhat low on freon, typically would be due to a slow leak somewhere. (If it were a rapid leak, the system would be empty and would not run at all)

Look for dirt stains around the AC pipe connections, especially at the discharge hose fitting on the compressor and the condenser inlet and outlet fittings


Instead of dumping the freon out and pulling a vacuum to start from scratch, I'd just add a little and see what happens......
I'd have pressure gauges on both high side and low sides so I can see what the system is doing inside........add freon maybe one ounce at a time until it is cooling again and the pressures look right.
The whole system only holds maybe a pound, it's real easy to get way too much then it doesn't cool worth a dang. Just a couple ounces over or under spec can really hurt the cooling efficiency.

If you use the stuff with dye in it, then later on after it leaks out you can get a blacklight and look around for the evidence.

Saratoga

I will get some gauges and give that a try.

What is your opinion on using a refrigerant with a stop leak. One manufacturer states that their product will seal gaskets and hoses, another states that their product seals metal, gaskets, and hoses.

ezone

As a professional with a license and certifications, I'm not a fan of sealers.

Stop leak can ruin the expensive freon recovery machines we professionals use.


Some types can ruin your AC system.