In 1999 Chevrolet released a new pickup bearing a familiar name: the Silverado. In 1999 and 2000, Chevrolet offered the classic C- and K-series trucks alongside the new Silverado pickups. In 2001, the Silverado replaced the C- and K-series trucks altogether. The 2005 Silverado came in three sizes, 1500, 2500HD and 3500HD. Chevrolet gave customers many options on all three versions of the 2005 Silverado, so knowing the correct fluids to add to the truck components is imperative.
General Motors recommends 5W-30 conventional engine oil on all models of the 2005 Chevrolet Silverado, in most cases. In extreme weather — temperatures that fall below -20 degrees F — GM recommends 5W-30 or 0W-30 synthetic engine oil. In all cases, check that the American Petroleum Institute certified the oil and that it meets GM Standard GM6094M.