Air leak “whistle hiss” while idling- help

Most likely a bad air governor to regulate pressure. Air lose is probably not related.

 

I had a main airline burn off with the wires it was bundled with, they rubbed through and shorted out, result was a straight leak from the compressor, result was the same wierd spiking pressure built up and just about cooked my compressor. I had a bit of extra length so I could trim it out and used a quick connect to repair. Wires were a lot more involved, lol.

 

☝️☝️ What he said. I'd definitely start here.

 

If its holding half its air over the weekend I wouldn't lose sleep over it. The leak(s) are so small they aren't even worth wasting the time to look for IMO.

 

Sounds like a safety “pop-off” valve on an air tank could be letting the pressure out when it gets to high then reset itself when it goes halfway down. They are usually set to not allow pressure build up higher than 140-150 psi. in the system.

 

#### my tri axle dump loses all the air over night.

 

Governors are usually the first suspect in the cause of the pressure spike. And the surge/pop-off valve is doing its job in that case.
I had one go bad that every time that day I’d hit a pretty good jarring bump on a rough ranch road it would pop-off at normal psi. I’d have to physically push it back closed then build psi back up then go down road till the next dang bump. That was a new one to me at the time. Replaced it that night and moved on.

 

I've seen a gummed up governor cause purge valve to stick. If you've got an SKF air dryer I've seen those purge ports stick very often.