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Cummins ISM CM876 Vent Hole?


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Got the rig home and started working on a few maintenance items.  My first diesel, slowly working my way up the learning curve! 

Just noticed this opening in the back of the engine block, just behind the head.   Appears to be a vent ?   

Should there be some type of vent plug in this opening ?   

I remember reading something about a "slobber tube" is this related?

Thanks!

 

 

Cummins Vent Hole-2.jpg

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I'm also suspicious of what looks like a wiring harness loom close by.  What is inside it?  I would think that your model year engine would have a closed system with the crankcase vent feeding through the crankcase vent filter.  By any chance, is there also an opening on your crankcase vent filter?

 

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Not sure of the vent filter, I assume this will come off the head.   I'll need to look at that. 

The wire loom contains a wire that attaches to a sensor(?) on the head.

See wide shot below:

 

 

Engine-Vent Opening.jpg

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I just talked with a friend who has a 2009 Dynasty with an ISM engine.  And sure enough his engine also has the same opening like yours.  Now I'm wondering why there would be such an opening with what looks like an o-ring inside.  Are you able to put your finger or say a bent piece of heavy wire in the opening to see if there is a plug seal below where you see the hole?

You could also register with Cummins Quickserve (free) and once logged in, enter your engine serial number.  Then look at the engine parts list and see what goes in this opening or if it is sealed below the opening.

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My ISM has the same 'hole' in the block as pictured. Since I only had few steps to walk to it, I went and looked. The opening is blocked about an inch from the top and what looks like an o-ring is in fact the ridge of what looks like a freeze plug situation. Granted, mine is black with a red top but the hole is in same place.

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Thanks Ivan - That answers the question.  A freeze plug makes sense.  That would be plugging off the coolant from the head.

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Thanks Frank and  Ivan, didn't think to stick my finger in there!    Mine is definitely leaking a bit.  

Thanks for the Cummins QuickServe tip, I will definitely do that.

Bob

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Registering with Cummins QuickServe will allow you to register both your engine and generator serial numbers.  You then have access to all the service manuals, parts lists and service bulletins.  It does limit you to only 5 engine serial numbers per account but for an individual user, that's more than enough.

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  • 4 months later...

So they only replaced just a seal? I have a wet spot there too and it was my understanding that the seal is part of the Jake harness connector that would have to be replaced as the whole set, the whole harness. So I just clean it up once a while. Maybe yours is different or I was mislead. Do you have a part number they replaced? Thanks 

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Reviewed the service invoice and it stated that the wring loom services the fuel injectors.  They replaced two o-ring seals ($9.53 ea)  and replaced the valve cover gasket($165.85).  Sorry, no part numbers on the invoice, be glad to call if you would like.

I've only put about 60 miles on the coach since the service, so I don't know if this fixed the issue. 

 

 

Edited by LakeBob
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