Extreme Duty Marine Semi Synthetic 20W-50 Engine Oil

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Extreme Duty Marine Engine Oil Semi Synthetic SAE 20W-50

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Lucas Extreme Duty Marine Semi Synthetic 20W-50 Engine Oil is designed for use in high performance boats requiring the ultimate protection.

Lucas Extreme Duty Marine Semi Synthetic 20W-50 Engine Oil is manufactured with the highest quality paraffinic base oils and is fortified with an exclusive additive package containing high levels of Zinc, Moly and Phosphorus that provides a tougher, thicker additive film for maximum protection even under the most sever conditions. It lowers oil temperatures, extends oil life and minimizes metal fatigue.

Lucas Marine Semi Synthetic 20W-50 improves the film strength between the cylinder  wall and piston rings and slows oil burning while improving pressure levels in worn engines. It has good cold temperature properties and stands up to high operating temperatures. This product is compatible with methanol and all racing fuels.

Key Benefits

  • Excellent for use with supercharged, turbo charged or nitrous oxide high performance engines
  • Protects against rust and moisture during long periods of storage
  • Safely blends and is compatible with synthetic and non-synthetic oils
  • Dropping point 540 lbs
  • Provides rust and corrosion protection in both fresh water and salt water environments
  • Effective Water Resistance
  • Long Lasting
  • Resist Extreme Pressure
  • Extreme Friction Reducer


  • #10654 - 1 Quart (Case of 6) - 12 lbs
  • #10811 - 5 Quart (Case of 3) - 31 lbs
  • #10667 - 5 Gallon Pail (1 Pail) - 40 lbs
  • #10668 - 55 Gallon Drum (1 Drum) - 440 lbs


Product Spec Sheet Technical Data Sheet
Safety Data Sheet Safety Data Sheet
zinc Zinc Values

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Mark McDaniel uses Lucas Oil Stabilizer in 1984 F-150 4wd pick-up

I have a 1984 F-150 4wd pick-up that has over 175k on it that I bought off my brother. He was a big believer in your product and had always used your oil treaatment when it was time to change oil so I cuntinued using it and even started using it in my other truck.

Last Friday (04-13-07) I changed oil in both of my trucks and added one bottle of oil treatment in each. Little did I know that when I removed the old filter on the F-150 the seal remained stuck to the block and I screwed the new one right on top of it. I crancked up and continued filling the motor with oil. The next day I drove my truck to the store in town about six miles away in pourring down rain. When I got out I smelled oil and thought nothing of it deciding it was just oil I had spilled on the manifold. When I came out of the store I climbed in and set sail for home, never considering all the oil present on the water in the parking lot had just been pourring out of my truck. It took until the next day for me to investigate the new lifter tapping noise my truck was making only to discover THERE WAS NO OIL IN IT! I went back to NAPA and repurchased supplies and performed the job correctly this time and after all that my truck is still running great. I GIVE YOUR OIL TREATMENT ALL THE CREDIT FOR SAVING MY ENGINE - YOU GUYS ARE GREAT. THANK YOU!!!

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