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Old 01-15-2022, 06:32 PM   #1
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Cat C9 Acert Engine

Are these engines problematic?
In an Ď07 Country Coach.
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Old 01-15-2022, 08:58 PM   #2
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If the coach has the C9 with the serial number starting with C9S I have heard they are problematic. Is this the case?
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Old 01-16-2022, 04:45 AM   #3
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Like doodad said.
Note that the C9S came out in 2007. Your Coach being a 2007 "model year" would have a 2005 or 2006 "engine year" - so a C9 (not a C9S).

The C9 is a very good engine.
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Old 01-22-2022, 07:45 PM   #4
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Originally Posted by CountryB View Post
Like doodad said.
Note that the C9S came out in 2007. Your Coach being a 2007 "model year" would have a 2005 or 2006 "engine year" - so a C9 (not a C9S).

The C9 is a very good engine.
I donít own the coach as of yet. But looking at it seriously. It says Cat C9 Acert. I will certainly check to insure itís not an S model. Am buying an older coach because of no def.
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Old 01-22-2022, 11:34 PM   #5
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I lived the nightmare of a 2009 Coach with a 2008 C9s. Do not mess with a C9s under any circumstance. I would take a fleet of 20 DEF equipped motorhomes to maintain than maintain one C9s.

I’m not even sure a real life C9s exists in a commercial setting anymore, probably just in seldom used motorhomes. There is no way a company could stay in business relying on one.
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Old 01-23-2022, 09:12 AM   #6
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Cat C9 Acert Engine

The majority of C9 engines produced (about 10,500) were 2004-2006 vintage starting with engine serial number 9DG. As mentioned the 2007-2010 serial numbered C9S are problematic with the after treatment system - separate DPF with diesel and igniter head built into unit. There were a sour 1,200 of these units.

I know of one 2008 C9 Allure that has had issues with a C9S C9.

Check engine serial number before buying.

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ace, cat, engine

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