Originally Posted By: virginoil
The Mobil 1 15w50 seems to make the engine quieter and smoother than the Mobil 1 5w50 this is not in my mind.
I think there are a Couple of things going on here:
1) Sometimes, People WILL put an Oil that is TOO HEAVY for their Engine. ... And just like someone at the Gym that has Just Started, or whatever the Case may be.. its simply -TOO HEAVY!- .. And the Engine will feel Weighed Down.
Example: 10W-40 in a 1988 Honda CRX.. Felt like LEAD... SLUGGISH Engine!
Perhaps this is a Part of it.. although not certainly all the time ((M1 15W-50 seemed like the way i was gonna go, had my BMW lasted.. the BMW likes Heavy Oil, as does my Jaguar. American Car that says "Use 5W-30" should be fine with that grade.)
2) I believe we are ALL overlooking the :Oil Film." THIS FILM IS WHAT I THINK IS DOING IT!!!!
For example: MY oil now.. 10W-40 (Result after "Mixing" grades of Same TYPE of Oil. Safety First.) -- So, i have a "40-weight" Film! PLENTY of peopel say the Jaguar 4.2L Inline-6 i have considers "30-Weight" to be Too LIGHT! "Film will Break" OR not Cushion the Bearings enough!! .. I agree. So, i have a nice "40-weight" Film. My Oil PRESSURE is 40Psi at Hot Idle, and "60Psi" Hot running down the Road (Relief Pressure is 65Psi, not sure...) .. But if a certian brand and Grade of Oil is making yoru Engine's Rodds/Crank/Cam/ "Rotating Moving Parts" MOST HAPPY (Chemical Composition, Film Composition, CUSHION being provided) ... THEN its liek sitting on a sOFT PILLOW vs sitting on a THIN pillow! (For the Mocing Parts.) So perhaps it is THE FILM.. Im sure this can "Make an Engine Smoother?"
3) Last thing is.. "Felt and Heard." To FEEL a Difference.. See 1. to HEAR a Difference.. .. Willa Heavy enough Oil (Film) "Quiet" and/or Stop" "Valve Ticking"? OR is it the Make-up of the Oil?
Just soome insight, and observations.. Thanks!
1985 Jaguar XJ6 4.2L Inline-6
152,000 Miles
10W-40 after 2 Qts 5W-30 Full Synth MaxLife; 4 Qts 10W-40 MaxLife Synthetic Blend; and 2 Quarts MaxLife 20W-50 Synthetic Blend.
.. Post #2.. 3 coming Later.