Rotary air compressor oil cooler

I am working on an gas powered air compressor, maybe 120 cfm or so. The engine is not running yet, but will be soon. I know that the oil cooler leaks, I think it is steel and looks rusted at the bottom of the tubes. When craning the engine with the battery you can hear air leaking out of the oil cooler. Can this be repaired, and if so by who? Is the oil cooler on a compressor under the full operating pressure (125 psi) or is the pressure in the cooling circuit reduced? Can I find an oil cooler off some machine in the junkyard that will work, or do I need one made for a compressor? It looks expensive, I'm betting more than the compressor is worth. Thanks,
Josh

I've worked on alot of different brand rotary screw compressors and as far as I have seen they are all pressure lubed. In fact they usually have a minimum pressure valve on the discharge side of the reciever/seperator chamber that maintains, usually, around 80 psi of pressure in the system, for lubrication purposes, even if your load draws more CFM than the compressor puts out. In other words the answer to your question is yes, the cooler is under full system pressure.

As far as repairing one of the coolers I've never had it done myself so I can't say with 100% certainty one way or the other on that. However I will say that most of them I've run into are steel due to the pressures involved and as such are not usually repairable, at least not by anyone I know aout, if the leaks are in the areas I believe you are meaning the are.

With all of that said, what brand and model compressor are you working on? I know where a few older ones are setting, and I run across one on occasion here and there, so if I know what to look for I just might know or be able to find what your needing.

Worst case scenerio take a look at the link. I've never done business with this place but I found them awhile back when looking for a cooler to go on a hydraulic system that had an abnormally high backpressure on the return system to the point that 'standard' coolers wouldn't work. The customer wound up selling the machine before anything was done but I kept link for future refferebce. Good luck.
Pressure rated coolers