Customer Ratings & Reviews

I've been using Amsoil for quite some time now and after switching over to Amsoil Synthetics I noticed a big improvement in the equipment engines with there synthetic oils . In the cold weather that we have in the N E. the engines start better, and stay much cooler in Temp's in hotter weather over the other brand oils ... The synthetic oil from Amsoil is much more slipperier than the other oils allowing the engines have lower temps in hotter outside temps'. staying cooler and running better and longer life from your engines , the oils make the engines run better with less friction on metal internal parts . Giving a little more power and milage from you machines weather a Truck pickup,ATV,Tractor,big or small and your Zero turn mowers , chainsaws, weed wackers . Yes Use it .

I have a diesel with over hundred fifty thousand miles on it and uses less than a half qt. between oil changes. This is one great oil.

My while family has ran this in their vehicles for years. It's all we run. Good oil good price.

Great oil so far but it is very expensive and not happy about price increase

Best oil on the market

I have been using Signature Series 5W-40 Diesel Oil since 2018 and I have to say that It’s the best synthetic oil out there. It’s the only oil I use in my 2013 Ford F-250 6.7 liter turbo diesel. I highly recommend this oil for your diesel truck.

I have been using Amsoil for years now and currently have close to 350k miles on my Ram 3500 without any engine issues. I would recommend this oil if you want an oil that can withstand the extra temperature and stress put on an engine running 11-12 hrs. a day 2-3 weeks a month.

I really love the oil quality , the Duramax engine work amazing

Been using this oil in my 2019 Ford F350 Super Duty Lariat with the 6.7L Powerstroke Diesel engine and so far so good. Engine runs clean and smooth with zero issues. This is really good oil.

Pulling a 15k # boat, you want to have the best protection you can give your engine! This is the best you can get!

I run my duramax quite hard and have for many years. This oil in my mind is the best. I’ve had no issues internally and even more surprising I have noticed the oil to be less dark on change intervals than other brands which is incredible for a diesel in and of itself.

Excellent

OIL SEEM TO BE WORKING FINE ONLY BEEN IN THE TRUCK FOR 200 MILES

Highly recommend!

Best oil out there, especially for extreme conditions

It’s great oil. Just did my last oil change and I think it will be the last. As it is already expensive and they increase the price , and made me pay for shipping. That was the last purchase.

I love the Diesel oil, as I love Amsoil period, very high quality oil, I use their oils in all my trucks, tractors, zero turn, and side x side.

great oil

Have been using this signature series for a great number years in a 2004.5 Cummins haven’t had any issues

great oil