Duragard Synthetic Blend CK4 15w40-1 Gallon (Pack of 3) Meets WSS-M2C171-F1

Great price for three bottles. Get it for my tired old 350 in my GMC truck. PQIA.org test show around 1200ppm zinc/phosphorus levels and very good performance in cold crank, volatility mass% loss and viscosity retention at high temperatures. All good things for flat tappet valve train and old motors with enlarged clearances on crank and cam bearings due to wear. I run the 15w-40 in warmer weather and the 10w-30 they make in the winter months. My truck loves the oil and the quality at the price point is hard to beat. The three blue bottles the 15w-40 comes in are vented in a really cool way that when you pour it doesn’t glug like a lot of other bottles do, smooth poor. The 10w-30 comes in a big 2.5 gal jug so keep a few of your bottles from the 15w-40 and it’s easier to handle. Both are CK4-SN which means Gas or Diesel engines and of course backwards compatible. Awesome product. Will buy it till they either raise the price or quit selling it.