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Cleaning air intake system stem to stern

August 09, 2014, 10:42:51 am

I posted recently about turbo issues and foreign object damage. I'm ready to bolt on a new turbo but want to clean all piping including inside of CAC.  It appears I can water flush it in place, let it drain, siphon water out of exit manifold of CAC even reach inside and sponge up.  Will blow out with weed eater if necessary but I don't want to run until I know everything is clean.  When piping is reconnected I intend to clamp every joint and also wrap with fusible silicone tape.  Looks like i dodged bullet on engine damage, good oil p, no smoke, clean oil analysis.

I recommend everyon double check intake piping for integrity.  An told leaks on suction side can be  detected by lightly spraying joints w. Starting fluid in hole engine is running and listening for rpm increase.  Mine all looked OK but obviously wasn't.

Would appreciate any thoughts on cleaning scheme and  CAC geometry.

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Re: Cleaning air intake system stem to stern

Reply #1 – August 09, 2014, 10:58:43 am

Also possible one of the filter replacements earlier in its life was not properly installed, someone (STUPIDLY) removed the filter element and banged it on pavement to remove some of the dirt.  This can easily break some of the pleats and allow dirt in.  A common cause of "dusted" engines.

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Re: Cleaning air intake system stem to stern

Reply #2 – August 09, 2014, 12:14:21 pm

 Chuck, not sure how easy you can take CAC off but I would highly recommend it. When I was repairing mine (4 holes about a 1/4" each) I found it very easy to remove the panel and unbolt it off Rad'. It is a simple flush out and with air will remove almost all water. I gently heated the casting and left it open at both ends for a day(standing on end) and never had any problems once back in.
While it was out I closed both ends off and put a guage on one end and an air line on other. Built up 45lbs and left it for a few hours. No drop in pressure so I knew my repair was good, and boost has been excellent ever since.
reading Wolfe's comment about trying to clean filters may be one source of contamination but I also believe more likely that the air filter chambers on most coach's are not free of all the crap that gets in there from roof top. I looked at one at FOT while it was in for service and it was full of crap and leaves. I think that is a bigger reason for contamination.
JohnH

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Re: Cleaning air intake system stem to stern

Reply #3 – August 09, 2014, 12:42:56 pm

I replaced filter right after acquiring coach and pulled it first time yesterday.  No sign of damage or dust tracks around big end gasket.  I take Cummins at their word to not over service filter.  I'm thinking this turbo damage was a leaky intake system or some event w prior owner.  Maybe the blowout and off road excursion in Mexico....

John, I can pull CAC but don't see it as necessary unless I'm overlooking something.  Not too worried about a small amt of moisture in CAC as they commonly have condensate in em depending on temp and humidity.  Can always fire coach up with output disconnected for a few seconds.

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Re: Cleaning air intake system stem to stern

Reply #4 – August 09, 2014, 02:03:50 pm

Chuck, we had a turbo replaced on our previous MH, 8.3 Cummins, Cummins Atlantic years ago. There was oil in the CAC and they leaned it in place with a wand shooting either hot water or steam. Can't remember about drying it. Never had any problems for 10 years or so when we got our FT.

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Re: Cleaning air intake system stem to stern

Reply #5 – August 09, 2014, 05:51:29 pm

Thanks Dick, if its good enough for Cummins Atlantic then it suits me.  I want that sucker clean and not blowing any fod into the intake.

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