Just did a complete oil change and also have an aux external oil cooler. I'm now getting some oil pump whine. Anyone had this before? Any issues with the latest oil types?
So I take it you went to a full synthetic? I know Delo 400 ISOSYN is a blend but it’s my first time of hearing your issue while using it. Interesting to say the least
I can't use the Shell in my truck. I've had people ask me why my truck ticks so loud. Switched back to the Delo and within 5-10 miles of driving very quiet again.
Some trucks prefer one oil to another. If the full synthetic version stopped your oil pump whine then I would say you're making steps in the right direction. Another option is to try another manufacturer's oil.
I always used the ISOSYN - last 10 years. Added the external cooler and that's when i heard the whine. Full SYN must flow a litter better - best guess.