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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Dave Coberly uses Lucas Transmission Fix in his 1990 Chevy Astro

About 2 months after just having a transmission fluid flush, I checked my trans dip stick only to discover my fluid had turned black. So I asked my mechanic about this and he said there was some kind of internal pump in the trans that seemed to have stopped circulating the fluid causing it to just sit in the pan and heat up. I was also starting to experience some slippage from 1st to 2nd and also from 2nd to 3rd. I was real concerned that it was time for a re-build. So, I had the pan dropped and this time I put 2 bottles of Lucas Stop Slip in and topped off the fluid and within the first few miles of driving the slippage wasn't completely gone but had improved by at least 75-80%. That was about 30,000 miles ago. The trans now has just over 230,000 miles and I just dropped the pan again to install a drain plug, change the filter and add another 2 bottles of Lucas Stop Slip. Now I can drain the fluid without dropping the pan. It cost me about $20 for 2 bottles of the Lucas Trans Stop, about $6 for the pan gasket, about $10 for the 3 1/2 quarts of trans fluid we added plus $40 labor for my mechanic. Now I'm good for the next fluid change. If this is all I have to do to keep my trans going, I'm a HAPPY driver! I have been using Lucas Trans Stop for many years and it has ALWAYS performed beyond my expectations. If your trans has a slight slippage, it will make it better almost instantly and if the slippage is worse, it will still make it better. If you have REAL trans problems, then nothing in a bottle will be able to fix it. I HIGHLY RECOMMEND this product as your FIRST CHOICE in solving ANY trans problems. Just walk in the auto parts store, ask where it is, buy it and put it in. Period. It will be the BEST $10 you could ever spend on your vehicle. "I" will guarantee that!

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