Choosing between 5W40 Synthetics

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Hey all, after some helpful comments I have decided to go for a 5W40 for my VQ35DE Nissan to be adequate for winter cold starts in Detroit Michigan but protect a little more at the high temperatures and offer more shear stability than my current 5W30 Mobil1, especially when I drive the car harder in good weather.

I see Rotella T6 5W40 and Castrol EDGE 5W40 as the two most common synthetics for this weight. I was wondering what would have the better base oil, and which one would have the better additives? I'm a bit hesitant about using HDEO for a naturally aspriated V6 but nobody has said it would cause any issues.

Any other recommendations under $30/5 quarts would be equally considered.

My OCI is every 3,000 miles with new WIX XP filters.
 
T6 is a very good oil and it's available nearly anywhere. Mobil 1, 5W-40 Turbo Diesel Truck is a truly great oil, with a robust additive package. However, both are a bit on the viscous side for Michigan winters.
 
Originally Posted by VQAndrew
Hey all, after some helpful comments I have decided to go for a 5W40 for my VQ35DE Nissan to be adequate for winter cold starts in Detroit Michigan but protect a little more at the high temperatures and offer more shear stability than my current 5W30 Mobil1, especially when I drive the car harder in good weather.

Interesting, where have you seen the oil mechanically shear and how did you determine that?

Also how do you know the existing oil won't "protect" at high temperatures?
 
Your OCI is 3K and you're really worried about high temps in Michigan in January?
smile.gif
 
Why not go with what the manufacturer recommends in viscosity chart? I doubt its 5W40.

Oil changes every 3K miles are a thing of the past. 5K or 6K now. More if synthetic.

Believe what is in owners manual. Dealer will suggest more often for more $$ in his pocket.
 
I'm not throwing stones, OP, but even here in the Cali Wine Country it can get cold on a winter night; 20's outside, 35 in the garage. Not bad, eh? But when I start one of our BMWs after they've been sitting for awhile in winter time, they crank slower on 5w-40 and the engines are stiffer for the first 4 or 5 minutes. Our C-class MB was the same way in winter on 5W-40, and it's not even that cold here. But I can feel it in the car. I think 5W-40 is not ideal where you live. I don't think 5W-40 in winter will hurt anything, I'm just saying I doubt it's ideal. Run 5W-40 in the summer months. How about Castrol Edge 0W-30 (now Belgium made, but "German Castrol") I use that oil more than any other oil I use, and have for the last 15 years. My SIG just shows a temporary experiment with something else. I always end up going back to "German Castrol". I think it would be ideal for you year round. I really like that oil, all versions of it over the years. Over time it's been consistently good. A lot the Chevy LS V8 guys use this oil. It seems to be a great overall package.

Anyway, FWIW,

Scott
 
Interesting fact ...

Pennzoil Euro 5w40 is thicker than Pennzoil Platinum 10w30 from 212*f ( obviously, it's a 40 grade ... ) all the way down to about -13*f. Even though it is a 5W compared to a 10W.

It is only at the extreme cold temperature range that the 5w40 starts to become less thick than the 10w30.
 
So in the winter time, say 10 degrees Fahrenheit outside, what would be thicker: 5W30 Mobil 1 or 0W40 Mobil 1? And then what about "cold-starting" in the summer temperatures, like if the vehicle has been sitting outside in 80 degrees for a couple days?
 
Originally Posted by ad244
7,500 Mile OCI & Castrol Edge 0w-40 if you really want to stick with a 40 weight.


^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ THIS ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
So where have you seen the oil mechanically shear and how did you determine that?

How do you know the existing oil won't "protect" at high temperatures?
 
Originally Posted by VQAndrew
So in the winter time, say 10 degrees Fahrenheit outside, what would be thicker: 5W30 Mobil 1 or 0W40 Mobil 1? And then what about "cold-starting" in the summer temperatures, like if the vehicle has been sitting outside in 80 degrees for a couple days?

You can use the Widman graphing tool and the viscosity data from the Mobil 1 website to see for yourself. It will show you exactly what you want to know.

https://www.widman.biz/English/Calculators/Graph.html
 
first off skip the XP filter rated for longer intervals but filters LESS. also skip the 40W in the winter as it will not benefit you + oils with wider spans need more viscosity improvers that get used up + add no benefits in cold weather. when the cold hits use a 5-30 synthetic + when it warms go to a 10-30 synthetic as i do for my VQ40 frontier. for serious cold weather open your wallet for a real synthetic PAO + or Ester based oil like Redline etc!!
 
M1 0W40 vs 5W30 ...

[Linked Image]



Here you see that the 0W40 is marginally thicker than the 5w30 all the way down to about -20*c ( -2*f )

As for starting on a summer day, at say 80*F , the difference between the grades is barely measurable. Both oils will pump just fine, with any differences being measured in fractions of a second.
 
Originally Posted by 4WD
Lots of folks pushing T6 for cars … but not Shell.


I hear you, I feel confident T6 will be OK, but why go down that path when there are many other suitable options easily available for your application ?

M1 or Edge 0W40
PP-Euro or Edge or Amazon Basics 5W40

VOA / UOA show T6 is still high ZDDP so for me it's natural application in petrol/gas engines is for racing or old-school flat tappet engines.
 
Originally Posted by SLO_Town
I'm not throwing stones, OP, but even here in the Cali Wine Country it can get cold on a winter night; 20's outside, 35 in the garage. Not bad, eh? But when I start one of our BMWs after they've been sitting for awhile in winter time, they crank slower on 5w-40 and the engines are stiffer for the first 4 or 5 minutes. Our C-class MB was the same way in winter on 5W-40, and it's not even that cold here. But I can feel it in the car. I think 5W-40 is not ideal where you live. I don't think 5W-40 in winter will hurt anything, I'm just saying I doubt it's ideal. Run 5W-40 in the summer months. How about Castrol Edge 0W-30 (now Belgium made, but "German Castrol") I use that oil more than any other oil I use, and have for the last 15 years. My SIG just shows a temporary experiment with something else. I always end up going back to "German Castrol". I think it would be ideal for you year round. I really like that oil, all versions of it over the years. Over time it's been consistently good. A lot the Chevy LS V8 guys use this oil. It seems to be a great overall package.

Anyway, FWIW,

Scott

^This!
You will hardly find anything better readily available.
 
Somewhere out there there's a XOM petro-chemist saying to himself..."Darn it, VQAndrew's spirited summertime driving just annihilated our signature 5w30 product!" ...‚

But if running a 5w40 helps you sleep at night, I guess that's all that matters.


Fwiw, there's VPB 5w40 (if you're going to run a HDEO) and Delo XSP 5w40 mixed fleet. Both very good lubes and under $30 for 5qts.
 
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