AMSOIL Signature Series 5W30 – Our best selling product

SAE 5W-30 Synthetic Motor Oil (ASL)

AMSOIL 100% Synthetic 5W-30 Motor Oil (ASL) delivers extraordinary lubrication in all types of automotive gasoline engines. By combining the industry premier synthetic technology with AMSOIL premium additives, AMSOIL ASL exceeds the higher performance demands of modern engines.

  • 28% more acid-neutralizing power than Mobil 1.3

Based on independent testing of AMSOIL Signature Series 0W-20 using the ASTM D6891 standard test.

Protects Against Engine Wear

AMSOIL Signature Series Synthetic Motor Oil develops a strong fluid film that keeps metal surfaces separated while its robust anti-wear additives further reduce wear in metal-to-metal contact regions for maximum engine life. The Sequence IVA Engine Test, which must be passed to meet the industry-standard API SN specification, simulates extended periods of stop-and-go driving. For 100 hours, the test engine cycles between 50 minutes of idling and 10 minutes of elevated rpm – conditions that encourage engine wear. The camshaft is then measured for wear in 84 locations and an average score is determined. We used Signature Series 0W-20, the lightest viscosity in the line, to further increase the severity of the test. AMSOIL Signature Series Synthetic Motor Oil provided 75 percent more engine protection against horsepower loss and wear1 than required by the industry standard, extending the life of vital components like pistons and cams.

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Printable Product Data Sheet for AMSOIL Signature Series 5W-30 Synthetic Motor Oil.

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Package sizes include:

  • 1-Quart Bottle
  • 1-Quart Bottles (case of 12)
  • 1-Gallon Bottle
  • 1-Gallon Bottles (case of 4)
  • 30-Gallon Drum
  • 55-Gallon Drum
After rigorous third-party testing, the cam lobes show little-to-no wear.
Lower number = less wear

Protects Pistons from Low-Speed Pre-Ignition

We armed Signature Series with an advanced detergent system that protects against harmful deposits and low-speed pre-ignition (LSPI). Most new engines feature gasoline direct injection (GDI), often combined with a turbocharger to boost power and improve fuel economy. These new technologies, when combined with a poorly formulated motor oil, promote LSPI and threaten engine operation. LSPI is the spontaneous ignition of the fuel/air mixture prior to spark-triggered ignition. It occurs in today’s advanced engines and is much more destructive than typical pre-ignition.

Original equipment manufacturers (OEMs) like GM* have addressed the issue by designing tests to determine a motor oil’s ability to prevent LSPI. The GM test allows up to five LSPI events to receive a passing score. Signature Series Synthetic Motor Oil provided 100 percent protection against LSPI1 – zero occurrences were recorded

Protects Turbochargers

Our unique synthetic formulation is inherently stable to resist oxidation and neutralize acids. Signature Series Motor Oil provides outstanding protection against deposits common to high-temperature engine environments. The tremendous heat and stress turbos create can cause some oils to break down and form harmful bearing deposits through a process known as turbo coking. Over time, turbos can suffer reduced performance or fail altogether.

We challenged Signature Series to the GM Turbo Coking Test, which consists of 2000 cycles of extreme heat soaks. An oil must limit the temperature change within the turbocharger to 13 percent or less to pass the test. Signature Series limited the temperature increase to only 3.6 percent, protecting theturbocharger 72 percent better than required2 by the GM dexos1® Gen 2 specification.




Extends Drains: Protection Guaranteed

AMSOIL Signature Series Synthetic Motor Oil provides reserve protection, allowing you to go longer between oil changes if you choose – up to 25,000 miles, 700 hours of operation or one year, whichever comes first*. Our unique synthetic formulation and long-drain additive system are inherently stable to resist oxidation and neutralize acids over longer periods. Signature Series is designed to deliver outstanding engine protection, cleanliness and performance over extended drain intervals – guaranteed. It provides peace of mind so you can fit oil changes into your schedule.

1 Based on independent testing of AMSOIL Signature Series 5w-30 motor oil, in the LSPI engine test as required for the GM dexos 1® Gen 2 specification.
2 Based on independent testing of AMSOIL Signature Series 5W-30 in the GM turbo coking test.
3 vs. AMSOIL OE Motor Oil
4 Based on independent testing of AMSOIL Signature Series 5W-30 in the ASTM D6593 engine test for oil screen plugging as required by the API SN specification.
* All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use. All products advertised here are developed by AMSOIL for use in the applications shown.

Preserves Horsepower

The extreme durability of Signature Series Motor Oil ensures your engine runs stronger, for longer. We installed Signature Series 5W-30 Synthetic Motor Oil in a Ford* F-150 with a new 3.5L Ecoboost engine to test its ability to protect turbocharged direct-injection (TDGI) engines from torque and horsepower loss during extended drain intervals up to 25,000 miles. Power sweeps were done at the beginning and end of the test to evaluate horsepower and torque retention. As the graph shows, Signature Series helped maintain engine performance throughout the 100,000 mile test.

Protection & Power
By  KRISTOFFER,  a  Verified Buyer  from  Horseshoe Bend, AR  on  March 28, 2024
I’ve been using Amsoil since I was young. When I bought my wife 18 Ecoboost 3.5L brand new, I broke the engine on and been running Amsoil w/a WIX oil filter. The truck now has 112k on it with NO phaser issues, NO sludge build up and the performance, fuel mileage and overall characteristic of the engine is perfect. Thank you Amsoil for making a great product and keeping our drivetrains perfect!

Limits Oil Consumption

Signature Series has a uniform molecular structure that limits evaporation and keeps it where it’s needed most – protecting your engine. Volatility (burn-off) occurs when oil gets hot, causing lighter molecules to burn off or evaporate. This leads to oil thickening, additive imbalance, higher emissions and oil consumption. The NOACK Volatility test is the industry standard for evaluating motor oil high temperature evaporation. It measures the percentage of burn-off after a motor oil is placed under constant airflow at 482ºF for 1 hour. A lower number indicates a better resistance to evaporation. Signature Series falls far below the API limit for volatility, reducing the need for frequent oil top-offs and limiting vehicle emissions.

Easier Cold-Starts

Signature Series Synthetic Motor Oil does not contain paraffins (wax) and stays fluid in temperatures of -58ºF and lower. Extreme cold causes other motor oils to thicken, starving vital moving parts of lubrication, accelerating wear and even preventing vehicles from starting. Signature Series provides 66 percent better cold-temperature performance for easier starting, better fuel economy, improved oil flow (as seen below) and reduced wear.

Maintains Protective Viscosity

We formulated Signature Series with superior thermal durability that resists breakdown better than conventional and synthetic motor oils. The Sequence IIIH Test uses the Chrysler 3.6L Pentastar engine to evaluate a motor oil’s ability to resist the damaging effects of heat. The test is conducted with oil temperatures of 304ºF, 100ºF hotter than normal operation, to accelerate oil thickening and deposits. Despite the extreme conditions, Signature Series kept pistons clean and held thickening to only 6 percent, a minimal amount compared to the proposed specification limit of 150 percent.1 This stay-in-grade performance helps maintain maximum power and fuel economy while also ensuring advanced technologies like variable valve timing (VVT) operate as designed throughout the entire drain interval.

1 Based on proposed ILSAC GF 5 Plus specification

Signature Series Reviews

Solved all my Problems

By  STEVEN,  a  Verified Buyer  from  Florida  on  April 05, 2024
My 2018 Chrysler Pacifica with 51,000 miles calls for 0W-20 oil but a technician at a Chrysler dealership told me if I switched to Amsoil 5W-20 Synthetic oil my engine would not only preform better but the cold start rattle in the mornings would be gone. He was right. This is an excellent product and I highly recommend it

Nothing Better I bet ya!!!

By  MICHAEL,  a  Verified Buyer  from  Kentucky   on  April 01, 2024
I’ve not found a better product flat out! If you are a DIY person you will easily be able to tell the difference just by feel alone. I run this in both of my Vehicles and I’ve had ABSOLUTELY NO PROBLEMS, Motors are happy, they run cooler & more freely. I bought once and I’m a lifetime customer. If tests are what you like to watch on YouTube watch Project Farm and he tests this oil compared to other leading brands there is no comparison Amsoil currently is the best on the market. I’m not paid or compensated in any way for this review.

0-20 oil

By  HARRY,  a  Verified Buyer  from  Indianapolis   on  April 01, 2024
I was committed to Mobil one until I saw all the reports on AMSOIL I cannot believe after switching to AMSOIL that this is the same truck I changed all the fluids rear differential front differential gearbox transmission I’m getting close to 5 mpgs a gallon better gas mileage plus this trucks so quiet shifts better rolls better I couldn’t be happier