Air compressor ticking
04-22-2019, (Subject: Air compressor ticking ) 
Post: #1
Air compressor ticking
Hey guys I need some info. Cm871 air compressor just started ticking but stops when the air system is full. Is this the start of a bad compressor head that needs rebuilding. Thanks. Oh also I looked in the archive msgs and really didn't see and answers of what causing the compressor ticking
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04-22-2019, (Subject: Air compressor ticking ) 
Post: #2
RE: Air compressor ticking
Possible head problem, maybe a ticking unloader valve, could be an air leak between the air gov and compressor, could be the little 4" air line from the compressor to the intake is split. Or if you haven't had the truck long it could be just the nature of the beast and you just now noticed it. Cm870 and cm871's are very well known to rattle or tick while building air and stop once the governor pops off. I'd check all the above 1st. If that all checks out and its only while the compressor is building air, I'd say its the nature of the beast. One final thing i can think of you can check and I've seen guys on other forums report it solving their ticking is checking the cam gear timing with the proper timing wedges. Checking mine never solved the rattle/ticking but it never hurts to know for sure if a cam gear has slipped.
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 Thanks given by: Bigstank , Rawze
04-22-2019, (Subject: Air compressor ticking ) 
Post: #3
RE: Air compressor ticking
Ok will do thanks. I have noticed that it doesn't tick 1st thing in the morning when I start the truck cold but once it warms up to operating temp it ticks. I've had the truck 2yrs and it just started ticking for a couple of weeks now. I have seen and heard other compressors with the same tick on a few trucks next to me. Maybe it's just a Cummins thing like you mentioned
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04-22-2019, (Subject: Air compressor ticking ) 
Post: #4
RE: Air compressor ticking
Mine has ticked from day one. Even through a full rebuild with new compressor and later new dryer (AD-IS) I've been told it is a Bendix thing with the AD-IS but I don't fully believe them. The system works as it should and is moisture-free so I just get over it....
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 Thanks given by: Bigstank
04-23-2019, (Subject: Air compressor ticking ) 
Post: #5
RE: Air compressor ticking
A lot of Cummins does this even from back in the day. I’m not sure why but it a trademark of them as soon as they get a little wear. I wouldn’t worry about it as long as it’s building air properly.
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04-23-2019, (Subject: Air compressor ticking ) 
Post: #6
RE: Air compressor ticking
To prolong ( unloader valve ) life ...
Take off the intake to the compressor.
Drain air .
Take air tool lubricant and slowly pour into intake with the compressor running .
( Very slowly).
****ONLY do this with engine running and compressor in , or you could be buying a new one .****
All done .
This keeps the unloader valve lubricanted .
This would have saved me 2800$ ca.
I think a guy should do this every 6 most to a year .
If you are worried about your dryer ,just unhook the line going to it .


User's Signature: The missing link
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 Thanks given by: Bigstank




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