While your car has a 124 body and mine a 126, they both have M103 motors. I see 1 bar at idle fully warmed up using either dino 10W-40 or 20W-50. Also see 3 bar as soon as it gets to about 1500 rpm.
1991 300-SEL - Model 126
M103 - SOHC
James Madison - Oppressors can tyrannize only when they achieve a standing army, an enslaved press, and a disarmed populace.
Liberty Firearms Training - After years of trying to regulate California criminals with a never ending stream of gun control laws they have still not given up with the belief that if they make something a crime that criminals will miraculously start obeying the law.