Any thoughts on using Penzoil 15w40?
08-25-2006 | 05:07 PM
#31
Three Wheelin'
Joined: Nov 2004
Posts: 1,645
Likes: 1
From: Evanston, IL, USA
Originally Posted by anonymousagain
Chris - you're referencing the Multi-grade chart, not the Synth chart 
Consider that it ISN'T on the Synth chart, because there's more flow/better oiling from the lower 5w/10w weight and the 50 higher/hot number is still covered...essentially the Engineer is saying, "Why not get better flow (especially cold/startup) with the same hot 50 weight coverage".
Don't get me wrong, 15w-50 M1 - great oil, although IMHO a 5w makes more sense for cold/startup coverage.
Consider that it ISN'T on the Synth chart, because there's more flow/better oiling from the lower 5w/10w weight and the 50 higher/hot number is still covered...essentially the Engineer is saying, "Why not get better flow (especially cold/startup) with the same hot 50 weight coverage".
Don't get me wrong, 15w-50 M1 - great oil, although IMHO a 5w makes more sense for cold/startup coverage.
08-25-2006 | 07:00 PM
#32
Rennlist Member
Joined: Nov 2005
Posts: 861
Likes: 1
From: NorCal - Bay Area
IIRC, Mr. Hillary clarified not too long ago that a quality 40w Synth (eg, RotellaT 5w-40) has the same hot viscosity as a 50w (eg, M1 15w-50) at ~200deg normal oil operating temp...not sure how much hotter it'd need to get before a 50w is beneficial, or even if it could ever get there 
[FWIW - Walmart <by me at least> carries RotellaT 5w-40 Synth for $16/gal and I've had good pressure and temps even on 100deg days with AC. I would never have tried it if Mr. Hillary hadn't pointed it out as a "best of". Anyway, it seems like a bargain compared to M1 @ nearly $7/qt.]
[FWIW - Walmart <by me at least> carries RotellaT 5w-40 Synth for $16/gal and I've had good pressure and temps even on 100deg days with AC. I would never have tried it if Mr. Hillary hadn't pointed it out as a "best of". Anyway, it seems like a bargain compared to M1 @ nearly $7/qt.]
