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Multi-Displacement Engines and Engine Oil Viscosity
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Multi-Displacement Engines and Engine Oil Viscosity
I have a new (coming up on the first 500-mile oil change) Dodge Ram 1500 with the 5.7 hemi multi-displacement engine. It says to use 5W-20 regardless of the season. I've read that I have to use 5W-20 because the multi-displacement system will not work right with any other weight of oil. Is this right? Also, I live in Arizona which is hot and dusty, and most of my driving is city driving. How would this affect oil changes for even the extended life 15,000 mile oil? Thank you
-- Les Strickland, Gilbert, AZ
Since this is a new vehicle, you should definitely follow the OEM recommended oil viscosity and drain interval while the vehicle is still under warranty.  It is possible that the hydraulic design of a multi-displacement system is dependent on using certain viscosity products. The systems can be sensitive to aeration/foaming, and lower viscosity oil can help in this area. In climates where it is hot and dusty, it is always safer to use a shorter drain interval due to the possibility of a greater amount of dirt entering the oil system especially if the air filter system should tear or leak. As for higher temperatures, this environment would also benefit from a higher quality and/or shorter drain interval. For dirty and dusty conditions we recommend shorter oil change intervals, even with our extended drain products.
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