Thook, thook without air cleaner. None audible with

[CSARebel916]

I had this exact noise in my old 6.9. The engine sat for about a yr, and I put in my old 79. Fired it up and all you heard was thook, thook. I just let it go and after a week or so it stopped all on its own. Hopefully you can figure it out! Good luck!

 

[Fordsandguns]

My 91 does the same thing. Has done since I first got it. Everyone I have talked to says it's normal, that all of the Ford IDIs do that. My father in law has an 86 one ton that he put over 500,000 miles on with it doing that. He says everyone he has ever heard run makes the noise. I have heard lots of them around here doing it and until I found this site I thought it was just the way they ran. I drove mine for two years and no problems. the noise has never changed or anything.

 

[Diesel JD]

How old are your injectors? What about the pump? Timing? Could be a slightly unhappy lifter, but its almost surely not a rod or main bearing and you pretty much ruled out swallowing a valve so it should at least not hurt it to drive back to Virginia

 

[Dirtleg]

Yeah I started thinking about the injectors after my last post. Also could be a lifter. How do you diagnose that? Seems pretty impossible unless it destroys itself. Perhaps I have a weak injector. And to answer your question they are old (gray paint). Pump is new. (5 months)

Anyway I said I'd post a video once it was back together so here it is. I was disappointed at the sound quality captured by my camera. The thook noise is not pronounced in the video but it is very clear in person.

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[Diesel JD]

Well, you probably have to pull the intake to check the lifters and cam, but the injectors can just be pulled and taken to a good diesel shop..a good shop charges little or no money for this service. Personally I'd wait on that till you get back to Virginia, especially since you seem not to have real good support where you are in terms of a good work area and I doubt anythings getting ready to crater. It actually sounds real good in that video. I think I hear what you mean though. the only thing that might be a concern is that you say its a new noise. If those injectors are original at 240K miles its probably way past time for some new ones and they may veyr well be weeping causing your noise.