# 15w40 in a 10w30 truck?



## travis91 (Jul 26, 2005)

can i use 15w40 in my ford ranger that calls for 10w30? i think the thicker oil wont burn as quick as the 10w30 id only use it in the summer where the temps are above 85deg outside.


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## joejeep92 (Oct 11, 2010)

It is a common practice to do this. Keep in mind what the numbers mean though. The 10 or 15w means what the viscosity is at during winter or cold weather. The last number is what it is at 212 degrees Fahrenheit so 10w40 might be better for a all year round situation. I run 10w40 in my Jeep Cherokee that is supposed to take 10w30 with no problems. Also might look into the Lucas line of additives...great luck with them


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## HermitJohn (May 10, 2002)

Says you live in southern Alabama. You wont have any problem. I run straight 30wt when I can find it (straight weight oils are hard to find ) here in NW AR. No problem. when I cant get 30wt, then run 10w40 or 15w40. Old engines leak and thin oil leaks faster. The thin oil recommendations are for EPA fuel economy ratings. Thin oil gives slightly higher mpg.


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## Ky-Jeeper (Sep 5, 2010)

My 4.0 Cherokees oil pressure was very low in hot weather. So I run Shell Rotella 15w40 with 70psi at operating temp. I'll go back to 10w40 sometime this fall.


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## uhcrandy (Sep 16, 2010)

If its a new vehicle, you might want to be carefull. The 15w-40 is usually a diesel oil, and has lots of Zinc and Molly. This has been dropped for modern vehicle because it is hard on emission systems. In fact it will void your warrenty. Also newer vechicle have a different oiling system. They run thinner oil, sometimes as low as 0w, but depend on higher volume. This is different than the older vehicle. Now if you have an old, worn-out engine a heavier oil is an option.


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## joejeep92 (Oct 11, 2010)

Don't know of any newer ranger that recomends 10w-30. That mostly got phased out in the late 90's


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## travis91 (Jul 26, 2005)

Its a 1988


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## joejeep92 (Oct 11, 2010)

Youre good then. Highly recommend lucas products though


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## Sawmill Jim (Dec 5, 2008)

Shucks i been putting 15w 40 in my big truck ,pickup ,forklift and lawn mower everything but the wife's car eep:


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## unioncreek (Jun 18, 2002)

When I lived in MT I ran 15-40 diesel oil in all my pickups, even in the winter (-40). Never had any trouble with oiling and they all had way over 100K on them. 

Bobg


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