Question Help identifying older Mako 3 stage

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I finished cleaning and reassembling the pump. Last night I installed a power cord and ran it briefly for the first time. Total run time was likely 10 minutes. Any observations and suggestions would be much appreciated.

I connected the pump output to the cascade system just for access to the pressure gauge. The bottle valves were closed so I was just pressurizing the lines.

I did not change the oil because I wanted to get some idea whether the pump was functional before investing any more into it. I ran it with the old intake and final filters in place. My goal was to see if the pump would build pressure and whether the relief valves and auto shutoff would function. I believe the auto shutoff is likely set around 4400 psi.

  • The pressure rose to 4100 psi and leveled off continuing to run. I shut it down and made the following observations.
  • At least one of the supply connection to the cascades was not tight enough and was leaking. I could hear it leaking after I shut it off. A quick tighten stopped the leak.
  • The drain valve from final oil/water separator (gold one connected to final filter) also had a slight leak. Tightening the valve reduced but did not stop the leak. I will likely will have to replace the valve or at least disassemble and clean it.
  • There are probably other small leaks and I expect the various leaks are why the pressure leveled off at 4100. I will eventually work through all the connections with some soapy water and see where the leaks are but I wanted to stop and get some input from this forum before I go any further.
  • The intermediate separators seemed to have a lot of emulsion when I drained them for such a short run time but I don’t have any experience to compare to. It was mostly in the second one between stages 3 and 4.
  • After shutdown, I noticed vapor coming out of the air intake housing. I don’t know if it was oil or water.
  • The oil in the crank case seemed to be “boiling” for several minutes after shutdown. I could hear it and looking down through the top vent I could see it bubbling. At first I thought it might actually be water in the system boiling but since the oil reservoir exterior was not very warm I assume it was air leaking back through the lower stage cylinders or the oil pump.
Any thoughts? Why is the top of the crankcase vented back to the air intake housing?
 

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Old compressor, and getting some leakage back through into the case - could be rings, could be valves. My old MAKO/Bauer did that....
 
4100 psi is 900 psi beyond the machines capacity. It is a 3200 psi machine. That explains the carbon buildup you found in all the lines. They were cooking the oil.
That tube separator is not rated for those pressures and neither is any other part of the machine. Turn the auto cut off down to 3200 and the machine will probably live a long happy life.
 
https://www.shearwater.com/products/peregrine/

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