In a common, everyday multi-grade oil, the first number is the oil’s viscosity rating at -17.8 degrees Celsius (0 degrees Fahrenheit), whereas the second one is its rating at an engine’s ...

Weight This is the oil's viscosity, expressed as a number like 5W-20. The 5 in this example is the cold viscosity and 20 is the hot viscosity at the engine's full running temp.

The second car that I ever owned was a 2002 Chevy Silverado 2500 with a 6.6L Duramax diesel engine under the hood. It wasn't my first choice, but it was a hand-me-down from my father after my 1993 ...

Choosing The Right Oil For Your Duramax When the Duramax 6.6-liter engine first came out in 2001, GM recommended three motor oil weights. If the temperature was frequently below zero but not above ...

Ratings such as 10W-30 and 15W-40 are measurements of the oil’s viscosity, which is broadly defined as its thickness or weight. For so-called “multigrade” oils, such as 10W-30 and 15W-40 ...