viscosity confusion still.....

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Oil guru's.....since joining this forum, and reading numerous used oil analysis I have been convinced to use what my owners manual states to run in my vehicles now......and not deviate from it....but could someone tell me why when I spoke with mobil 1's tech department, and asked them the question "why are european spec's different than USA regarding viscosity (0w40,5w40) vs (5w30,10w30)....I was told "because they do not care about CAFE standards....or fuel economy..they want the BEST protection and that is why they use xw40 oils" This goes against the reasoning that "thicker is not always better",...and that thinner oils flow faster, and cool better,..but thicker oils provide a better "cushion" between metal parts. More confusion for me now....I should not have even spoke with them. Chime in all!!
 
Hmm.. That's an interesting point. Kinda makes sense. But of course thicker in colder climates is worse.
 
I feel you bro! Especially when our Aussie brothers show us a Valvoline website(OZ site) where 10w30 is called Low Vis! And I also remember an Aussie telling us the Prius comes factory filled with 20w50 down there!

The use of lower viscosity oils in America does have alot do to with CAFE. However since I have seen Ford F150's with over three-hundred thou on the odometer running only 5w20 I begin to wonder if stout 5w20's are the way to go. used oil analysis have shown the 5w20's to work good.

I believe the rest of the world will follow suit shortly...
 
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I have been convinced to use what my owners manual states to run in my vehicles now


Not a bad place to start.

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but could someone tell me why when I spoke with mobil 1's tech department, and asked them the question "why are european spec's different than USA regarding viscosity (0w40,5w40) vs (5w30,10w30)....I was told "because they do not care about CAFE standards


Well, we don't much care about how many engineers they employ to complicate stuff for a career. They don't have CAFE ..so they don't care
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or fuel economy


This probably isn't completely true ..they handle it differently.

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they want the BEST protection and that is why they use xw40 oils"


They want oils that fit through the hoops that they make them jump through. These tend to be 40 grade synthetics. They have a real knack for alpha-numeric soup over there.

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This goes against the reasoning that "thicker is not always better",


Only if you're a European.

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and that thinner oils flow faster,


Lighter oils flow easier.

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but thicker oils provide a better "cushion" between metal parts


I like a firm mattress. Euro's are sissies.

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I should not have even spoke with them.



Well, I think that I would have grabbed on to the "they want the BEST protection" ..I would have immediately shot back, "..and what do I want, assured neglect?" ..and timed the pause.

You exist in a margin that is, for most drivers .. in most services, very broad. If one perpetually pushes the edge of the envelope ..in a routine manner ..over an extended service life ..with wear and deposit standards ..with fuel economy standards ..it would appear that special synthetic grades have been designed and blended to suit that need.
 
Gary is in rare form!

Simply put, the guy/gal you spoke with is wrong.

Sure the Euro's want the "best protection", but that does not mean they use 39" wall thickness condoms.
 
Originally Posted By: Gary Allan
Well, I think that I would have grabbed on to the "they want the BEST protection" ..I would have immediately shot back, "..and what do I want, assured neglect?" ..and timed the pause.


Well said, Gary!

Europeans are on a different plane of existence. On a variety of levels, they don't understand us any better than we understand them. Both sides are probably a bit too pedantic on the oil issue if you look at it broadly. "Their" cars seem to do fine on "our" oil, and vice versa.
 
The big difference is that Europeans tend to run much longer OCIs than Americans. I wonder if thicker is better for that, expecially if they are taking dino out to 15,000 km.
 
A German couple came to stay with my brother a few years ago. While here, the German guy would rev the rental car routinely up to near redline in normal driving. That is what he is used to doing. He said he routinely drives about 100 mph on the Autobahn in Germany. That's just something to consider about differences between Euro drivers and North American.
 
Originally Posted By: JAG
While here, the German guy would rev the rental car routinely up to near redline in normal driving.
Guy sure knows how to live. I have to do that more.
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JAG - Actually, your German friend was not displaying normal European driving, but normal American driving technique - for rental cars!

The bottom line is that it is still somewhat mysterious why the same vehicle is spec'd for different oil viscosity depending upon where it will live. Europe needs gas saving oil more than we do.
 
Originally Posted By: JAG
A German couple came to stay with my brother a few years ago. While here, the German guy would rev the rental car routinely up to near redline in normal driving. That is what he is used to doing. He said he routinely drives about 100 mph on the Autobahn in Germany. That's just something to consider about differences between Euro drivers and North American.


you hit the nail on the head..with our low speed limits our cars see nowhere near the stress that Europeans put their cars under routinely driving well over 100mph for extended periods of time ...

that is why they need 40wt and we don't
 
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I dunno. I didn't even feel like I was moving in my BMW until 80+mph. They appeared to design it just right so that all the fun noises didn't appear until above that speed. As you approached 100mph ..it was sorta a choreographed experience with the landscape markers starting to whip by.. working in concert with the increasing output of the exhaust. 80-85 was normal commuting speed. Below it, it was like speed suitable for surface streets.
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If in the US a car is driven for 7,000 miles using a 5w30 conventional, it may be sheard to a 20 wt at ~ 5,000 miles. Take the same oil and run it for 15,000 miles and it may unusable. If it started at a 50 wt then it might still be a 30 wt at 15,000. As stated the mileage at change time has a lot to do with the starting viscosity. I checked the recomendations for my cars (Subaru & Mazda) the the European & US oil viscosity recomendations are the same, The viscosity recomendations between European & US are not necessarly different. I suspect that some of the recomendations for heavy oil come from self appointed oil experts and will not be found in owners manual or on manufactures web sits. Ed
 
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