Product Reviewed: SAE 5W-20 Signature Series 100% Synthetic Motor Oil (ALM)
Current Rating: 4.95 out of 5 stars
Votes & Reviews: 528 vote(s) and 1218 user reviews.
Reviewed by Stu: 
I've used AMSOIL exclusively in my previous and current Jeep Grand Cherokee Overland. I learned of Amsoil through an Internet search looking for the best motor oil. I'm more interested in the quality of the oil than I am with extended intervals. I trusted the reviews and comparisons and I felt the difference in the performance of the 8 cylinder Hemi. Just seems(s) to run more smoothly. I can't see/feel any difference between the Signature Series and the previous flagship BUT I'm now consistently getting 20mpg on my daily 120 mile, highway commute. Prior to changing over to the SE I was at 18-19mpg so something has changed for the better.
Reviewed by Al:
I just put this oil in once a year and forget it.
Reviewed by Fuzz:
I have been using Amsoil synthetic oil since the 70's. This was at the recommendation of my father in law who was a professional master mechanic for a large public utility company. Amsoil synthetic oil and grease has been used in all of my vehicles over the last 40 years without any internal engine failures. Easy starting in below zero winter temperatures without any hammering or pounding noises. For clean and efficient engine performance there is nothing better than Amsoil synthetic products!
Reviewed by Downtown:
Signature 5w20 from first oil change in my 2014 fiesta st.
1.6 liter ecoboost, 60k later I still can't see tracing on cam lobes and motor is spotless. 13k oil changes/ oil reports show no unusual wear metals. Viscosity stays consistent,
tbn over 3 and NO oil added between changes. Looking forward to see longevity of this mill!
Reviewed by Don,:
I have used this product in my 2012 Ford Explorer since I purchased it in February of 2012. I drive about 20,000 miles each year and it only change oil once a year. I have not had to add oil between changes.
Reviewed by Mustang Fiend:
The oil was perfect for my 2016 Mustang GT. I wouldn't buy any other brand, only the best for my baby.
Reviewed by Old timer:
My truck uses 8 qtrs and I was not wanting to change the oil every 3 to 4 thousand miles so I used Amsoil for the best protection and duration. I use Amsoil in all of my transportation. Never had a mechanical problem. Start out with the best and don't worry.
Reviewed by Don:
From it first oil change I have used Amsoil 5w20 and to this day runs like new. In fact all my engine run in Amsoil products. Very happy with the performance and durability it keeps giving.
Reviewed by BK:
I've been using Amzoil products in all of my vehicles since 1988.
Reviewed by Rumen:
For all my cars
Reviewed by Facta Non Verba:
We now use Amsoil 5w-20 Signature Series + Amsoil EA-Series Oil Filter on a 2004 Lincoln Towncar. Mixed driving mileage improved by 3 mpg over the OEM oil + filter, and highway mileage increased 5 mpg. The engine runs much smoother, particularly at idle. So far, the 5w-20 Signature Series has demonstrated itself to be of the same exemplary quality consistent with other grades of Amsoil Signature Series.
Reviewed by Mark:
I used this oil in my wife's 2010 flèx and we just turned it in with 150k miles on it and the car engine was running like it was brand new. It cost a bit more but well worth it. In fact we just bought a new 2016 flèx and this is the only oil I will use. I bought enough to change the oil until she reaches 100k. I also use their diesel oil for my 2006 Ford F-350 diesel.
Reviewed by Facuanj:
I only used AMSOIL products in my vehicles.
Reviewed by Raz:
AMSOIL synthetic is the best!
Reviewed by Skippy:
Best oil ever.
Reviewed by
Die hard Boys fan in Texas:
Ive got Amsoil in everything from my 87 Bronco to my 06 Expy. Motor oil transmission fluid in both. My wife has the European oil in her Turbo Beetle and my mowers have the 4 stroke small engine oil. I use everything from zrod 20-50 to 5w -40 European turbo safe oil
Reviewed by Ed:
Best oil period
Canada
United States
I will continue to buy this product.
I have used this oil for several years with very satisfactory results. The only drawback is that it is priced in American dollars and starts to become expensive when the exchange rate widens.