Been chasing a scary noise that sounds like a power steering pump failing, except that mines rebuilt recently.
Seems to come on with heat soak, not so much cold.
RPM related, comes on over 1000 rpm, goes away under 1000 rpm.
Then sometimes it doesn't come back over 1000 rpm, and more and more often it is coming back over 1000 rpm.
Thought maybe a failing (squealing) water pump shaft/seal/bearing. Replaced it, no luck.
Can the diesel fuel pump make intermittant noise like that?
Can the balance shaft(s) do something weird?
All belts are brand new, both timing, both accessory.
Had the alternator rebuilt last year, it failed in less than 12 months, now I'm running a junkyard alt with 110K on it, seems to make electricity. Could be making the noise, have no spares unfortunately.
Tried to record the noise with my phone, I'll see if I got a wav file to post.