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Is it Okay to Use a Higher Viscosity Oil Than What's Recommended for a Vehicle?
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Is it Okay to Use a Higher Viscosity Oil Than What's Recommended for a Vehicle?
I recently changed my oil to 15W-50 Mobil 1 Extended Performance. I have an old 1990 Toyota 4 Runner with 275,000 miles, rebuilt 75,000 miles ago. I discovered this web site after changing the oil myself and discovered you recommend 10W-30 Extended Performances. Do you recommend I change the oil to the recommended viscosity? What are the trade-offs of leaving the 15W-50 in my 4-Runner? I live in southern California where it gets hot, so I assumed (wrongly, it appears) that a higher viscosity would give better protection.
-- Frankie Duran, El Cajon, CA
Either Mobil 1 viscosity grade will provide outstanding protection and performance. For an older vehicle there is a occasional benefit sometimes in using higher viscosity grade oil especially if you are beginning to use more oil due to normal wear and tear of a high mileage vehicle. If your vehicle is not consuming much oil switching to a lower viscosity oil such as a 10W-30, or even 5W-30, can provide you some fuel savings as these lower viscosity oils can provide better fuel economy. And because of the Mobil 1's reputation, you can be assured of excellent protection even at these lower viscosities.
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