Hello all. Putting thread here to get more input. Yes I was a Saab head. This is my first MB 07 E550 RWD. Amazing torque and smooth as silk. Only concern I have is at cold idle engine is quiet. Hot idle engine has bit of a diesel rattle to it. If I raise rpm to 800 it’s quiet. Only 95k miles with dealer Mobil 1 oil changes. I assume oil pump etc. same on all 5.5. I used MB 5-40 and MB filter last change with no noticeable difference. Being a high volume low pressure oil pump should I try lighter viscosity for more volume or heavier viscosity for more cushion. Maybe oil pressure bypass problem. Was told under oil filter housing is port to check oil pressure. What is considered good oil pressure at idle. Thanks in advance for any suggestions. K