NOT SEEMINGLY BOOST RELATED. I wanted to get that out asap. Started today. D13, 514k. Coming up hills noticed a weird noise, almost like a sucking/grinding noise from pass side which can only be detected under load. Immediate thought was one of the pulleys or something on the front of the engine was going out or CAC has leak/leaking hose. Pull over, get out and check, no fluids, no noise, just this pain in the ### still turning. Bump idle up as high as I can get it, nothing. Floor peddle a few times while parked, nothing- no noises whatsoever unless under load and is doing it seemingly regardless of boost as it will do it regardless of turbo whine and boost pressure. Get back in and drive (78k gvw right now) at around 1,300 rpm noise kicks in. Pull over, idle and kick boost, no pressure loss, no leaks that I can find in the dark at the moment. Power is still smooth, leaning away from egr valve. Belts, pulleys, tensioners all sound and look good. Fluid levels the same as they were this morning. Noise very obviously coming from pass side. Jesus Christ don't let it be the turbo. I really am at a loss here. Thoughts?
If it is the turbo? Then it must be. Eliminating all else what is left must be the truth. Im half tempted to wonder if you were lugging it. But obviously you been pretty good with your inspection so...
1,300+ rpm only. Definitely not noise from lugging as the truck always runs between 1,000-1,500 rpm. I'll admit when I'm on flat ground and in an environment that is mostly coasting I'll run it around 900 for a short period of time. Oh and my lower 5 too. Eaton 10 spd. Original trans, feels like it's had work done. Dealer didn't know. Very tight on gears but clutch is...let's not talk about the clutch. Turbo seemingly fine. Functioning, building and holding boost quickly with no fluctuations in boost gauge. No weird whines or jumps/loss of power.
You said tensioner; but how did you check it? How about A/C pump? Can you pull intake hose aside, and get ahold of turbo spindle and try to wiggle it? Hate when the gremlins hide.
Just pull test and didn't see any movement. Praying it's a bearing on a bolted on component up front but I really don't see how that could be what with the noise being present at 1,300+ rpm under load and not 1,300 rpm not under load. Sense dictates bad pulley bearing is gonna sound off at 1,300 with or without strain on it, right? AC pump crossed my mind too, but I doubt it. I think this is gonna be one of those issues I find myself on the back of a tow truck with.
Mentioned the tensioner cause I had issue once and limped it home by spraying it with WD-40 oil. Hate to ask this one, did you Try moving the water pump pulley around?
I hate gremlins too. Having been around heavy equipment all my life, I do know that "spinning things" act differently under load. E.g., once had a water pump that would weep only when the AC compressor was pulled in,,,, same belt. Just food for thought.
Ok Sir. Here is my last card. Im thinking Detriot 500 here. Bear with me if you have a different mill under there... Hotel power off the engine (Accessories) are usually gear driven and there should be like two or three belts driving a couple other stuff maybe if that usually the fan. Here is a real crazy thought, that fan bad? As ready to shake off? Maybe you got a newer electric fan. I don't know. Im just tossing cards on the table...
I had a cat that did that. Started leaking in philly southbound one morning, I had a rule smell coolant you are leaking. But looked everywhere nope no green fluid. Made it to Kenly NC and shut down for the night. Poof a lake of coolant via the water pump when she contracted from cooling around the bad seals by morning. That was a interesting wakeup... I wasnt sure what was what... from the fumes etc.
