Automotive Air Conditioning Information Forum

This about a brand new Vintage Air R134a system in a hot rod. I used a small Robinair vacuum pump to pull down to 28"-29" indicated. When I close the manifold valves, the vacuum slowly drops, around 1" every few minutes. So, I decided to see what it did with pressure. I statically charged the system to 50 psi, and 2 hours later it was down to 45 psi. During that time, we were unable to find any leaks using soap and water.

The next morning it had dropped to 36 psi. Started the engine (with compressor not energized) and after a few minutes the 36 psi increased to more than 40 psi do to engine heat, no doubt.

But here are my questions: It does sound like we have a very slow leak somewhere, right? The entire system is new, and the compressor has oil from the factory. And if it's the leak is that small, would fully charging the system and letting the oil circulate tend to seal up the leak? Or should I just bite the bullet and buy or borrow a sniffer?

Thanks.

Sounds like a leak. But first make sure that the leak is NOT in your gauge set/fittings.

I guess the gauges/manifold might be bleeding gas somewhere, but they were able to hold a 28-29" vacuum with schrader valves closed.

I heard earlier from my buddy across town who owns the car. He said after the pressure increased to 40 psi when he warmed up the engine, it had dropped only 1 psi in the next 6 hours or so.

Think I'll go ahead and fully charge the system this week, then borrow or buy a sniffer if we run into problems. We do have a 12-pack of R134a!

On another note, if anyone here has questions about the Vintage Air Gen II systems, I can probably answer them. We have had just about every problem known to mankind, from a pinhole leak in the coil to a controller board that didn't output the correct voltages to the air valve servos.

MikeB wrote:Think I'll go ahead and fully charge the system this week, then borrow or buy a sniffer if we run into problems. We do have a 12-pack of R134a!

I suggest that you add some UV dye to the system, then you could use a UV light and goggles to find a leak.


REMEMBER: DO NOT ADD ANY SEALANT OR REFRIGERANT WITH SEALANT. EVER.