Extreme Duty Marine SAE 20W-50 Engine Oil

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Extreme Duty Marine SAE 20W-50 Engine Oil

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

Lucas Extreme Duty Marine SAE 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 SAE 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

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* Size:


  • #10653 - 1 Quart (Case of 6) - 13 lbs
  • #10810 - 5 Quart (Case of 3) - 31 lbs
  • #10665 - 5 Gallon Pail (1 Pail) - 40 lbs
  • #10666 - 55 Gallon Drum (1 Drum) - 440 lbs


Product Spec Sheet Technical Data Sheet
Safety Data Sheet Safety Data Sheet

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Robert Welk uses Lucas Heavy Duty Oil Stabilizer for 1991 Chevrolet Caprice

Dear folks at Lucas Oil:

About four months ago I came across Lucas Heavy Duty Oil Stabilizer in one of our local Advance Auto Parts stores. I changed the oil in my 1991 Chevrolet caprice wagon with close to 140,000 miles at the time and put in a quart of the product. I don't fail to do the same every oil change now.

The product has already shown me an increase in fuel mileage per gallon, made the engine run smoother and also helped rid a rear main seal oil leak. Tuesday night of this week the thermostat stuck and the engine heat went out of sight on the gauge and the red "idiot light" came on for the first time in the seven years that I've owned the car. I thought I'd lost the engine. Not. thanks to the superior lubricating and protective properties of the Heavy Duty Oil Stabilizer the engine suffered NO damage, and once I got the hermostat housing cooled down, the thermostat unstuck and coolant back into the cooling system from the reservoir, the car drove the remaining four miles home without incident.

The next day the car drove just like always, smooth performance and normal engine temperature. I believe that without the product in my engine I'd be replacing the motor now. My wife's car also has the product in the crankcase and both cars will continue to have it installed EACH oil change.

Thank you,

Robert Welk

Martinez, GA

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