We have oil free compressor atlas copco zr 55.
After we replace oil seal ( seal ring p/n: 1202 5245 00) with non original part, we have this problem:

Element 1 Outlet Temperature reach 225 deg. Celcius.

Intercooler Pressure reach 3.9 bars.

Milky oil in oil tank.

We have checked intercooler, aftercooler, water separator, inlet valve, replace air cleaner; but all that actions didn't solve the problems.

Please share your experiences and knowledges.
Thank you


Hello Agung,

The high pressure and the high temperature are related to eachother and are the same problem. Higher intercooler pressure will result in a higher temperature of low pressure element.

Your intercooler pressure is way too high. Normally it is around 2 - 2.5 bar only.

The high intercooler pressure indicates that probably something is wrong with the high pressure element.

it is not compressing good enough anymore, or high pressure air is blowing back to the intercooler.

Where exactly is this oil seal located? I don't have the partlist/manual of this machine with me right now.

Milky oil could indicate that compressed is air blowing bubbles into the oil somewhere. There is no water in the oil, is there? Let the compressor stand still for a while and check if the 'milkyness' is still there, and if water has collected at the bottom of the gearbox.

Hope this was helpful and let me know if you need more info. Good luck!

Owner of air-compressor-guide.com

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