Cm 870 head being replaced

[Craag]

Greetings all, 1st time post.

My truck is an 05 9900i with a cm870 that shows up as 453 hp on serial number check but was stamped 435 factory on valve cover.

Truck had a total inframe at 906000 km now is at 1173000 km. Keep in mind it is at 32000 engine hours due to much PTO use. Not sure hours when I had it inframed but it was approx 5 years ago 270000 km ago. Head was replaced at inframe and injectors.

So the problem recently has been fuel in coolant/coolant in fuel. Dealer is certified Cummins but from what I'm reading here I'm guessing that doesn't count for much. I'd rather take your advise!

So let's get to what the dealer is saying. I mentioned to them about an updated service bulletin on replacing the lower injector o rings. They knew about cups on newer models but this was news to service manager. He looked it up and booked it in. After taking it apart they are stating that it won't work as the coolant is coming from the top and bottom of cup? So it needs a head. Here is where I'm getting cold feet as we began talking liner depths after I've been reading on here about .014-.015" protrusion to get a better seal with head. They were skeptical both the manager and the technician and mentioned that .009-.010 Is high and as long as it's positive you shouldn't need to worry about it with just head replacement.

How much extra am I getting into here if liners are lower than .014" but still positive protrusion? Should these be counterbored and shimmed to .014"? Head is not quite off yet. [/size]

Would a vibration dampner and bearing roll in be a good idea at this point?

Thanks for all the valuable info here!