2012 Mack Granite Air Compressor

[hrccws]

Hi, we have a 2012 Mack Granite, we just started having issues with the air compressor not building up air, after some diagnosing we found the unloader valves were sticking, we removed the head off the compressor and found the whole head was full of carbon, (this compressor was replace with new one approx. 6 months ago due to old compressor pressurising cooling system) we cleaned the head totally and replaced unloader valves and gaskets and about 2 weeks later we are getting the same thing happening, also getting a lot of crap and carbon like substance in the air tanks and filter, we have a 2011 one also which dropped a rod in the compressor a few years back but had no other issues, Mack dealer not offering any answers, has anyone had similar issues? it has a 2 cylinder Wabco compressor on it.

[hgfdg1990]

Did you check the steel braided oil return line could be lack of lubriaction to the cylinders and crank and thats what cuasing mass buildup so quick also,coolant lines if there is any restriction aswell as the steel line going to the compressor and the hose after that supplying to the air dryer has been changed aswell those usually clogg up if there is excessive buildup?, never really heard of carbon buildup that quick sounds like an internal problem in the compressor. i would also take out the line out of the dryer to see what comes out of there maybe it full of carbon and passageways are clogging up due to that could also cause loss of airpressure and other major problems

Edited November 8, 2015 by Bigmackdaddy77

[Mackpro]

We have seen this alot. We have not found an answer. We have seen the discharge line fitting get clogged with carbon and be slow to build up air. We remove fitting and clean out and all is good for a while.