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Q: Motor Oil?

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Just changed the oil and for the 1st time used a synthetic blend over 75,000 mile 10/30 oil. My oil pressure gauge is running about 10 psi lower than it normally did. Is the synthetic oil ok to run in it?

My car has 113000 miles.
My car has an automatic transmission.

Hi There, Contrary to popular belief, it will not hurt your engine when switching from synthetic to conventional or vice versa. In fact, Synthetic blend oils are actually a mix of conventional oils and synthetic oils. Many synthetic oils are made up of a base oil of approximately 80%, with other additives making up the remaining 20%. The main difference between the molecules in synthetically engineered oils and conventional oils are the uniformity of the molecules. The molecules found in most conventional oils differ in shape, size and impurity. The type of oil that should be used for a specific application depends largely on the driver’s driving habits, the environment in which the car is driven, the mileage on the car’s engine and the limits that the engine may be pushed to. With regard to the lower oil pressure you are currently experiencing, this may be due to the slightly more free flow of the synthetic oil vs the conventional oil previously used. The other thing to consider of course, is the viscosity of the oil. Assuming you are using the same viscosity oil (10/30) as before, this should not impact the change in oil pressure. I would recommend double checking the proper oil level as well by checking the oil via the dipstick to be sure the correct amount of oil is in the motor.

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