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1459 Views 16 Replies 13 Participants Last post by  fuzzy645
I was thinking about using 10w-40 oil in my truck is that fine or do i need to stick with 15w-40?
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I would stick with the 15-40 as it is designed for diesel engines and 10-40 is not. I am sure that there will be a lot of opinions on this.
 

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Discussion Starter · #3 ·
On the bottle it said it was designed for diesel engines diesel oil goes from 5w40 to 15w40 i believe i know for sure that its 5w and 15w thats why i was asking is it alright to run 10w in mine
 

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The first number tells you what the weight of the oil is cold. Since diesels are so cold starting up, the cold number is very important. Of Course my Camry and the wifes Scion Tc both call for 0w-15. BS, they are doing that for the EPA. I use 10w-30 starts up better and is quieter.
 

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i would go for the 5w-40 rotella, because it is available nation wide at wall mart
 

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Discussion Starter · #6 ·
so should i not use 10w-40 there is a sale right now on royal purple and they have that oil and its like 4 dollars a quart
 

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I like the Chevron Delo 15W40. It is cheap at Costco and it seems to be a very good oil.
 

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Ive allways used Shell Rotella 15w 40 in my Diesels... even in the winter until i went to school in the U.P. of Michigan, then i put 5w 30 in for the winter and it was fine, but then i drove to texas over spring break on the thinner oil and it did fine... oil never got too warm, stayed around 190 degrees, ran fine.... but ive gone back to 15w 40 for the summer.... but i would think you would be fine with 10w 40
 

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Ive always ran Shell Rotella T 15w 40 in all my diesels, never had a problem, great oil and its relatively cheap too...
 

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On the bottle it said it was designed for diesel engines diesel oil goes from 5w40 to 15w40 i believe i know for sure that its 5w and 15w thats why i was asking is it alright to run 10w in mine
if the oil is approved for diesel engines 10w40 is fine to use...
 

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If it has API class CI-4 or newer then you are good to go. If it is an older class or not "C" rated don't use it.
 

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15W-40 is way too thick for Alberta winter( -30~-40 w/ wind chill). I only use Rotalla T 15W-40 in summer & Rotalla T Synth 5W-40 in winter. the only downside is that 5W-40 lacks of towing power ( tow anything more than 5000lbs, I can feel it!!!). don't know why.
 

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I also live in norhtern Alberta- although its not -40 year round- I use 0w-40 made by Shell year round. Have used this in all my CTD's for a few years now. No issues at all pulling loaded sled trailers in the winter or a 8000# fifth wheel up a 15 mile 7% grade in 30 degree C weather.
 

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So long as the oil is rated CI-4 or CJ-4 you can use 10w40 oil in your engine. BTW, I use 5w30 HDD oil year round with out any problems.
 
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