10w40 over 5w30 diesel

Many questions first.
What engine are you refering to?
What vehicle?...FORD, GM, VW, MB, what?
How many miles?
What oil(brands & weights) have you been using?
How is this vehicle used?
Etc.
 
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10w oils will pump and flow at minus25 celsius, 5w oils will pump and flow at minus30-35 celsius.

How cold does the climate get in Georgia? pick an oil with a Winter rating appropriate for your climate.


SAE grades are measured at 100c, do you know how hot your oil gets in regular use? If you have a bottle of oil that claims to be 40, but you only get your oil upto 80celsius then your oil is closer to a 50. If that same oil goes up to 120celsius its closer to a 30.

So find out how hot your oil gets and pick viscosity based off of that.
 
It may not be totally accurate science, but almost every analysis Ive seen shows better wear numbers for a 10 or 15/40 than for the 5/40.One member running Mystik 15/40 always shows very very nice numbers compared to the 5 he ran in the earlier UOA.
 
mercedes sprinter 2009 2.2 diesel bluetec, 171k miles, 10w40 was used from the beginning as i saw in service book, dont know why
 
we dont have a winter here, temp goes down -5 for a month or so, mostly its above 0, have no idea how hot it gets, how do i check?
 
that is interesting, maybe because its thicker and reduces engine wear better? this affects fuel economy but engine will have longer life?
 
Originally Posted by Audios
It may not be totally accurate science, but almost every analysis Ive seen shows better wear numbers for a 10 or 15/40 than for the 5/40.One member running Mystik 15/40 always shows very very nice numbers compared to the 5 he ran in the earlier UOA.

UOA "wear numbers" have far more to do with engine specifics and operating conditions than with the oil. In fact, Blackstone has noted that there is no statistically significant difference between wear numbers for an appropriately rated oil. As is always the case here when numbers are reported no one has any clue whether they are significant or not.

People like to pin a lot of stuff on UOA results because it helps justify their oil choice and the expense of the UOA but in reality almost none of it is appropriate.
 
Originally Posted by angryorc
we dont have a winter here, temp goes down -5 for a month or so, mostly its above 0, have no idea how hot it gets, how do i check?

What 10W-40 oil are you looking at that has the approval your engine requires?
 
Originally Posted by Audios
It may not be totally accurate science, but almost every analysis Ive seen shows better wear numbers for a 10 or 15/40 than for the 5/40.One member running Mystik 15/40 always shows very very nice numbers compared to the 5 he ran in the earlier UOA.


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The brand, and thus the add pack, was also changed with those viscosity changes. Iron wear tends to come from areas that operate in mixed and boundary lubrication where the additive package is more important.
 
Originally Posted by kschachn
Originally Posted by Audios
It may not be totally accurate science, but almost every analysis Ive seen shows better wear numbers for a 10 or 15/40 than for the 5/40.One member running Mystik 15/40 always shows very very nice numbers compared to the 5 he ran in the earlier UOA.

UOA "wear numbers" have far more to do with engine specifics and operating conditions than with the oil. In fact, Blackstone has noted that there is no statistically significant difference between wear numbers for an appropriately rated oil. As is always the case here when numbers are reported no one has any clue whether they are significant or not.

People like to pin a lot of stuff on UOA results because it helps justify their oil choice and the expense of the UOA but in reality almost none of it is appropriate.

I am still searching for one Topic here on BITOG which has study in it that thicker (10w 15w) oils have better protection over thinner....due to HTHS coifficient....
 
Originally Posted by Kamele0N
I am still searching for one Topic here on BITOG which has study in it that thicker (10w 15w) oils have better protection over thinner....due to HTHS coifficient....

Well those look like winter ratings which don't have a direct correlation to the MOFT. But there's no debate that HTHS (and subsequently the MOFT) are what keep parts separated and prevent wear. Once they touch you'll get all the wear your care to have.
 
Originally Posted by angryorc
any mb 228.51 would be fine i guess, i use Castrol VECTON Long Drain 10W-40 E6/E9


That's a full synthetic 10w40 with a strong TBN and good number of approvals. I have 10 litres in my garage I'm keen to use but unsure what to use it on yet!
 
Ran 10W40 Mystik JT8 in my Ecodiesel, the 5 gallon pails were too cheap to pass up. Wouldn't hesitate to run again provided it's not freezing ambient cold starts.
 
Anyone used Castrol VECTON?. I have a Mercedes E class CDI, the oil does not meet MB 229.31 or above. Just wanted to get feedbacks from users.
 
Not many 10W-40 HDEO oils here in NA, almost all are 15W-40, 10W-30, or 5W-40.

10W-40 HDEO is a European thing, and most seem to be semi-syn or full-syn products, so should all be good quality.
 
Agree with 229.51 unless owners manual requires even more stringent 229.52.
Don’t get the 229.52 unless owners manual requires it.
Some Mercedes car/SUV diesels are ok with 228.51 as well.
Check Bevo; carefully.
I would recommend the 10W40 over the 5W30 if you don’t live in a place with cold winters (below-20C/ -4F).
I use 5W40 because lowest temperature last 2 winters was -17F = -27C. And surprisingly in 228.5 category viscosity 100C for 5W40 is higher than 10W40. I also go to the tropics.
 
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