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It sounds like you're describing injector noise. I'd imagine those'd be all worn out after all those miles. Have you checked them?
Yes it could. Can you run a balance test with your IDS?
Man, it's never easy with these 6.4s - I sure miss the old 7.3s!
Well, if the injectors are good, then I imagine there is no significant amount of diesel in the oil that could cause lifter noise. Plus, if you've checked all the usual suspects, such as oil press, valve clearance, etc. and found everything OK, then I would have to lean towards the pump as being the source of the noise. Have you checked for any type of debris in the fuel rail that might indicate that pump being worn out?
Having been retired for a while now, I've not actually seen one of these pumps go bad, but I have heard that they do. The one thing that has me thinking is what you said about the noise going away for a while after the repairs; could it be possible that there is oil dilution? I mean, I know you've probably thought of this before, but have you tried changing the oil and going with a heavier weight, like a 40 or even 50 just to see if the noise goes away? I'm thinking that if it does, then our problem is engine wear and not injection-related.
I'm thinking that 50 weight is gonna tell us what's going on for sure...
Welcome, I'm Chris (aka Moose). I normally log in after 3 pm central everyday. Please let me know exactly what you need from this conversation so I can provide EXCELLENT 5 STAR service.
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