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By: Joseph Schneider,


I have a Hitachi 2 HP 4 Gallon Oil-Lubricated Air Compressor Model # EC12.

Hitachi EC 12 air compressor
Hitachi EC 12 air compressor Photo: plumbersstock.com

The motor sounds strong, but I’m getting hardly any air in my tanks. I check the oil and and looked at the gasket and it seems to look ok. Air is coming out of the top of motor. Don’t know if that is normal.


Hello Joseph. No, air isn’t supposed to come out of the top of the motor. This symptom makes me think that you have a valve failure, and what may be happening (since air follows the path of least resistance) is that the air that’s being ingested by the compressor piston is being blown right back out the same inlet port since it’s easier for the air to flow that way, than down past a check valve into the tank.

Why won’t your compressor build air pressure? There are a lot of reasons found on the troubleshooting page of this site which may also be a cause, though I suspect it’s the reed valve that is causing your compressor problems.


Hi bill

by: Joseph

Is the reed valve the cylinder shape by the gauges that you can pull to release the air?


No, that’s the PRV, Joseph. The reed valves are located inside the intake hole (usually there is an intake filter screwed into the intake port) and they control the air in, and stop the air out, so that the air can be forced into the tank.