How to tell if Air Dryer is bad or needs the filter replaced?

Joy, doesnt mean its working. The filter is only there to catch the very small leftover vapor after the purge. Its a system, not one little part will fix the problem.

 

Your truck manufacturer will have a maintenance schedule for your air system. My truck was doing that, got water in the lines, (worked out in a while) the solution was new compressor and air dryer filter. How many miles on your truck? I think it might be better to go for the system solution, rather than one item at a time, but if your compressor is good (good chance it is if the water isn't oily) try getting the new filter. I just don't make any money with my truck sitting in a shop on the waiting list again. Best

 

If you have oil at the exhaust on the air dryer, there is no sense in changing the filter. Your compressor is blowing oil and the decadent will become contaminated in a short period.

 

I had the same problem. I could drive it a short distance and it would have a mist come out of the air tanks. Changed out the air dryer cartridge (as this was easiest and less expensive). This did not do anything for me at all, so then I took the line that goes from the governor to the air dryer (be sure to bleed all air out of system first) and cranked it up and watched what was coming out of the air governor and once I saw it was clean I knew it had to be air dryer.

Replaced the air Cartridge and no problems since then.

 

You need to do some troubleshooting before you go replacing parts. If your compressor is running all the time that will cause moisture in the system. Water in your system when it is warm is bad also. Just because it isn't freezing up like it would in the winter does not mean it is not harming valves or loading up brake chambers. Your truck is not made to operate properly when the air mechanisms are loaded with water.

 

I have the same issue but with my DD15 w/ 329k on here.... alot of water spraying from the tank now its has an oily smell....time to have the air dryer looked at

 

Crack the drain values of the tanks just enough to push a little bit of air out.