Customer Ratings & Reviews

The Amsoil Synthetics are so much better ,I get outstanding results using there Synthetic Oils . The 5W-40 Synthetic Oil for the Diesel engine is the best to use all winter, the engine starts easier in winter months and runs cooler engine Temps even in the summer hot days . There Synthetics provide easier starting in the cold days of winter as well as keeping all engine parts running easier ( Less Friction ) on those cold days and less friction and less heat build on the warmer or hotter days of summer . You can see lower engine temps in the summer when running , less friction on those metal parts means better mileage and less wear . I like all there Amsoil synthetic oils and greases. If you're not using the Amsoil Synthetics your wasting your money on the other oils you should be using there Synthetic Oils at Amsoil and seeing the difference it makes on your equipment by running better their Synthetic Oils are much slipper on all metal moving parts .

used in three trucks oldest an 01 with 275k purrs like a kitten

Using Amsoil motor oil for years,always count on the quality

So far I really like the oil. , it seams to be staying thicker

Great price

This product performs as advertised and tested. The engine starts easily in cold weather; it runs cool in hot weather. It protects the engine against excessive wear. I am a happy customer after using it in two different diesel engines.

Best diesel oil on the market...!!!!

Very good oil 15W40 SS Diesel oil is all i run in my duramax trucks.

Amsoil is the only brand I run in my vehicles and with extended drain intervals and proven results it’s a no brainer.

I love this oil. Have been using it for a long time. I have a 2005 Dodge 3500. My mileage went up to 23+ miles per gallon. Up 3 MPG. I don't drive as much since retired, so I change oil once a year. This is excellent oil for any diesel.

Great product and great company to deal with. I enrolled in the preferred customer program and it is great. Fantastic catalog and orders were shipped immediately.

I switched to this oil in my 2006 dodge Cummins. 1st start up with the Amsoil my engine sound quieter and felt smoother. Best oil I’ve used.