Oily water in air tanks

When was the last time you changed the dryer cartridge?
What motor do you have?

 

First off check/rebuild/replace your air dryer. Secondly figure out how much oil your getting. Ideally you shouldnt get any in the tanks but older trucks do pass some oil from the compressor.

 

If you replaced dryer I'm guessing it has a new cartridge. So most likely time for a compressor.
And if it's pushing enough oil to foul a cartridge in three months,then you need to clean out the dryer and get a new cartridge.

 

Is your compressor cycling excessively? A good compressor will pass more oil and put more condensation through the dryer if it's duty cycle is too high. Check that you don't have any air leaks, especially in the wet tank or purge/unloader circuit.

If everything is working normally, it may be time for a compressor. You'll also need to service the air dryer and replace the cartridge again.

 

Do you have any blue-grey smoke from exhaust?
Have you blown a turbo recently?
Been awhile since I worked on a Detroit. Does yours have the little foam filter off the intake. If so need to clean it.

 

could be worn out air compressor