A lot of oil coming out of air tanks and purge valve need help .

That's not what I mean. The extra air pressure from the boost of engine feeds the air comp. Putting more pressure in the cylinders of air comp. When you took the line off that runs from side of engine head to intake of comp was it saturated with oil?

 

The truck I have now was passing oil when I bought it,changed filters and stopped passing oil. You can't rely on the restriction gauge,have to look at them to see if they are dirty.

 

Here's the manual to follow to estimate oil consumption per Bendix

 

There will ALWAYS be a little discharge of oil. It is normal. When it gets where your air dryer is spewing oil that is excesive.

 

I have a 388 here doing that. Did you get yours straightened out and what was the problem?

 

I know this is an older thread. I just replaced my 3406 and need to attempt getting the oil out of the air system. I replaced the air cartridge and cleaned the air dryer out really well. What about the air lines and tanks? Can I dump a bunch of air line antifreeze down the hose and pressurize, drain the tanks and repeat?

 

Just changed the compressor and serviced dryer. They all worked out OK.