By 
JOSEPH, 
a 
Verified Buyer 
on 
December 15, 2025
Doesn't really get any better than amsoil, been running the product for years in all of my modified vehicles front to back with no issues. The price of this 15w40 is on point as well.
Bottom Line
Yes, I would recommend this to a friend.
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5 star rating
It’s a synthetic blend but …
By 
PAUL H., 
a 
Verified Buyer 
from 
Joplin, MO 
on 
June 30, 2025
It’s a synthetic blend but it’s a higher content blend than the rest. All my company trucks run it and it seems to working out great for all of them. Better fuel mileage and better engine temperatures!
Bottom Line
Yes, I would recommend this to a friend.
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5 star rating
My 6.0 loves it
By 
STEVEN, 
a 
Verified Buyer 
on 
June 07, 2025
Run this in my 2006 6.0 power stroke. Seems to be a better alternative to the OEM oil. Engine runs quieter and starts better. Zero injector issues.
Bottom Line
Yes, I would recommend this to a friend.
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5 star rating
Awesome
By 
JAMES, 
a 
Verified Buyer 
on 
May 27, 2025
Should’ve done this before if i love my truck! This is the best choice for my Kenworth T660, runs super nice, and no more garbage oil, or cheap oil on that expensive engine. Recommend 1000%
Bottom Line
Yes, I would recommend this to a friend.
Was this review helpful?
5 star rating
Endurance
By 
KEVIN, 
a 
Verified Buyer 
from 
Us East Coast  
on 
March 03, 2024
I’ve been using AMSOIL 15W-40 exclusively in my Westerbeke genset and Cummins 6BT5.9 for 18 years now. At every fluid change the analysis from Blackstone comes back with excellent results. AMSOIL is my engine fluids supplier…period!
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