The visco clutch with the fan is removed, the noise remains. I will drive the car in the evening, but I see it as a problem somewhere deeper. Crankshaft pulley bearing - harmonic balancer, or a problem somewhere with the engine timings, these are solved by gears (no belt or chain). Some ideas?
No tilt cab - access is handled like this
It seems like you now have a diagnostic method to figure out what’s causing the noise. Just have to eliminate each possibility one by one. I don’t recall many posts here about noises from fan clutches. I’ve had weird noises from my truck’s water pump though, which is part of the same assembly that turns the fan. In my case, means the water pump is about to expire. Humming and/or squealing noises from worn or loose accessory belts, belt tensioners and idler pulleys more common. Harmonic balancers do wear out, cause problems, but main problem for that seems to be engine timing is disturbed. Turbos, b/c they spin so fast, seem like they could make weird noises, but don’t recall many posts here about turbo noise problems. You could try the forum search feature, link upper right this page, searching for “turbo noise”, etc. If you have A/C, A/C components sometimes source of weird noises. Compressor, expansion valve, etc. Easy enough to prove/disprove that theory just by turning A/C on and off.
A bit of a problem is that the engine is so noisy that localizing the sound is not easy :). However, I still listen to the sound from the recordings and it has strange manifestations “independent” of rpm or speed. See in the link to the recording during deceleration, where the noise repeats when the revolutions and speed decrease, and the honk regularly at intervals of several seconds. (as if it releases excess pressure?)
That’s why I also thought of checking the pcm valve and sump ventilation system. I will check tomorrow.
