No longer use Mobil1 0w-40?
07-29-2010, 09:47 PM
#31
My logic is a little different than yours. I think that film strength matters when the engine is stressed, but I don't stress my engine until it's warm. Whereas, the valve gear in these motors is super sensitive to lubrication, and the more easily it flows the quicker it will get it on startup. In other words, when cold, your variocam bits need oil fast more than your pistons need maximum protection.
Anyway, sounds like we're both bringing knives to this gunfight, so I'll leave it there. I'm sticking with what my indie puts in there.
07-29-2010, 09:58 PM
#32
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OK, new guy diving in here... I think I've read this same thread 79 times on bimmerforums (my home)...
the point is not that 0-40 is bad, its that mobil1 0-40 is too thin or doesn't have the right chem compound. this exact same issue came up when BMW delisted mobil1 0-30 from its approved list, but kept redline/amsoil/etc....
now, from there... if you're getting ANY tappet/lobe mushrooming, I'd suggest you cease using whatever you were using before and move to something a touch thicker at operating temp.
flame suit: ON!
the point is not that 0-40 is bad, its that mobil1 0-40 is too thin or doesn't have the right chem compound. this exact same issue came up when BMW delisted mobil1 0-30 from its approved list, but kept redline/amsoil/etc....
now, from there... if you're getting ANY tappet/lobe mushrooming, I'd suggest you cease using whatever you were using before and move to something a touch thicker at operating temp.
flame suit: ON!
07-29-2010, 10:27 PM
#35
Dark Helmet, "at operating temperature", any oil with a 40 at the end of its rating has the same viscosity. It can't be "too thin". That oil has a 0 viscosity when cold, and a 40 viscosity when warm. If you want a heavier oil at operating temperatures, it's the second number you need to think about, not the first.
People pronounce 0W40 as "too thin" and, with respect, they often seem either not to know what they're talking about or to be kind of imprecise in their language. It's why I usually avoid these debates. If you believe that 0 is too thin, you must by definition believe that it's too thin at startup. Because when it's at operating temperature, the viscosity isn't 0. It's 40.
So I remain confused about why it's such a hot topic...
People pronounce 0W40 as "too thin" and, with respect, they often seem either not to know what they're talking about or to be kind of imprecise in their language. It's why I usually avoid these debates. If you believe that 0 is too thin, you must by definition believe that it's too thin at startup. Because when it's at operating temperature, the viscosity isn't 0. It's 40.
So I remain confused about why it's such a hot topic...
07-29-2010, 10:56 PM
#37
I called LN eng. about 6 months ago when I first had my P car to ask about the IMS thing, sorry guys you put the fear in me, and they told me it wasn't that big of an issue for warmer climates. He told me to use Castrol Syntec 5W40 and not worry about it. That's a fact. No bull.
07-29-2010, 11:02 PM
#39
Three Wheelin'
99% of this bantering is about the first few minutes after startup. After that, the oil thickens on its way to 40 weight.
My guess is that the times that 0 vs. 5 weight will matter are only in the coldest of conditions (e.g., below -25C) or if someone is stupid (desperate?) enough to slam the engine to high RPM's or high load immediately after starting.
I'd be willing to bet $$ that using your car regularly (so parts remain coated) and gently until it warms up -- will have more tangible, positive results than choosing 0 vs. 5 cold weight.
07-29-2010, 11:14 PM
#42
Actually, note that it says below -25C not 25C.
99% of this bantering is about the first few minutes after startup. After that, the oil thickens on its way to 40 weight.
My guess is that the times that 0 vs. 5 weight will matter are only in the coldest of conditions (e.g., below -25C) or if someone is stupid (desperate?) enough to slam the engine to high RPM's or high load immediately after starting.
I'd be willing to bet $$ that using your car regularly (so parts remain coated) and gently until it warms up -- will have more tangible, positive results than choosing 0 vs. 5 cold weight.
99% of this bantering is about the first few minutes after startup. After that, the oil thickens on its way to 40 weight.
My guess is that the times that 0 vs. 5 weight will matter are only in the coldest of conditions (e.g., below -25C) or if someone is stupid (desperate?) enough to slam the engine to high RPM's or high load immediately after starting.
I'd be willing to bet $$ that using your car regularly (so parts remain coated) and gently until it warms up -- will have more tangible, positive results than choosing 0 vs. 5 cold weight.
