LakeBob Posted April 10, 2022 Share Posted April 10, 2022 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! Link to comment Share on other sites More sharing options...
Frank McElroy Posted April 10, 2022 Share Posted April 10, 2022 It looks like there is an o-ring there. Can you post a wider view to we can see more of the engine? Link to comment Share on other sites More sharing options...
LakeBob Posted April 10, 2022 Author Share Posted April 10, 2022 Will do, I’ll get some more pics today Link to comment Share on other sites More sharing options...
Frank McElroy Posted April 10, 2022 Share Posted April 10, 2022 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? Link to comment Share on other sites More sharing options...
LakeBob Posted April 10, 2022 Author Share Posted April 10, 2022 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: Link to comment Share on other sites More sharing options...
Frank McElroy Posted April 11, 2022 Share Posted April 11, 2022 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. Link to comment Share on other sites More sharing options...
Ivan K Posted April 11, 2022 Share Posted April 11, 2022 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. 1 Link to comment Share on other sites More sharing options...
Frank McElroy Posted April 11, 2022 Share Posted April 11, 2022 Thanks Ivan - That answers the question. A freeze plug makes sense. That would be plugging off the coolant from the head. Link to comment Share on other sites More sharing options...
LakeBob Posted April 11, 2022 Author Share Posted April 11, 2022 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 Link to comment Share on other sites More sharing options...
Frank McElroy Posted April 11, 2022 Share Posted April 11, 2022 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. Link to comment Share on other sites More sharing options...
LakeBob Posted August 15, 2022 Author Share Posted August 15, 2022 The actual leak was from the wire loom going into the valve cover. This is the wiring for the jake brake I was told. The shop had to remove valve cover and replace the loom seal. Link to comment Share on other sites More sharing options...
Ivan K Posted August 15, 2022 Share Posted August 15, 2022 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 Link to comment Share on other sites More sharing options...
LakeBob Posted August 16, 2022 Author Share Posted August 16, 2022 (edited) 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 August 16, 2022 by LakeBob Link to comment Share on other sites More sharing options...
Ivan K Posted August 16, 2022 Share Posted August 16, 2022 Thanks Bob, I'll check it out when I have a good reason to take the cover off again. It isn't a big deal right now. My understanding was that the leak was known to be through the connector into the harness but maybe not. Thanks for the reply! Link to comment Share on other sites More sharing options...
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