When I bought my 2 cars — a 2005 Dodge Caravan 3.8L V-6 and a 2007 Dodge Caliber Dual VVT 2L — I got a lifetime oil change, which Meineke now services. Both the oil filler cap and the manuals state to use 5W-20 oil. Recently, the manager told me they no longer carry 5W-20 oil and their substitute is 5W-30 oil, which he said will work the same. He said that mostly all new cars use 5W-30 oil. Without ruining my engine, will 5W-30 weight oil be OK to use in my 2 cars?
5W-20 motor oil is recommended on many vehicles because it improves fuel economy by a slight amount. 5W, with the W standing for “winter,” is the rating for the oil’s thickness when cold, and 20 refers to the thickness at engine operating temperature. A 0W or 5W oil flows more quickly than a 10W oil at cold startup, providing a vital oil film between moving parts, reducing wear. Thicker oil is needed at operating temperature, due to increased stress on engine parts during a variety of speeds and loads; 30 is thicker than 20.
5W-20 motor oil has yet to match the universal availability of stalwart 5W-30 and 10W-30 oils, leading some folks to make substitutions. My personal belief is that 5W-30 oil could be used without any negative outcomes, but it’s best to stick with what the car maker recommends. My basis for this opinion is that many car makers originally made the switch from 5W-30 to 5W-20 on what appears to be the same engines, to improve corporate average fuel economy, or CAFE, standards. It’s odd that in the past carmakers offered a range of recommended oil viscosities, depending on weather conditions and driving habits. Now, in many cases the only oil listed is the one that promises to meet CAFE standards.