Is full synthetic oil really neccesary?

In many cases, semi-synthetic oil is fine. Dreamstime/TNS

Q: I bought new a 2018 Mazda6, 4-cylinder turbo. The specs call for semi-synthetic oil. Everyone who I know with auto expertise thinks I should use full synthetic, even a former engineer friend from GM. The tech personnel at my local dealership, including the manager, tell me to follow the specifications recommended. I called the engineering department at Mazda Corp. and a technical representative said, “stick with what you are using.” Any opinions?

R.K., Glastonbury, Conn.

A: Stick with what you are using. Although full synthetic is marvelous, it comes with a premium price tag. It can cost nearly double. Use it if you wish or if you win the lottery.

Q: I have a snowblower that uses two-cycle oil. Is it OK to switch between synthetic and regular two-cycle oil, and which is better to use? Also is it OK to buy several bottles of oil at one time, which will last me several years?

G.D., Harleysville, Pa.

A: You will have no problems switching between traditional oil and synthetic in either your car or your snow blower. Go ahead and stock up when it is on sale.

Q: I have seen on TV that you get 25 more miles to the tank full when you fill up with Amoco premium. We have Nissan Altimas. Nissan recommends regular gas. Will using Amoco premium cause any damage to the engine or void the warranty?

A.P., Chicago Heights, Ill.

A: Amoco’s pitch applies to a full-size pickup driven exclusively on the highway. A footnote on BP’s website says that the claim is “based on median difference between 93 octane Amoco Ultimate and 87 octane minimum detergent E10 fuels in late model full size half ton pickup trucks using EPA Highway Driving Cycle (HWFET). Assumes 100% of fuel in tank will be used. Results will vary based on what you drive, how you drive, and other factors.” Using premium gas instead of regular will have no impact on the warranty but will have an impact on your budget. According to the U.S. Energy Information Administration, there is roughly a 25 percent price premium for premium gas based on the most current prices as of December 7, 2020.

Q: I have a 2004 Toyota Camry with just under 60,000 miles. How often should I be changing the oil since I put so few miles per year?

C.R., Pembroke Pines, Fla.

A: You can’t go wrong changing your oil at 7,500 miles or once a year.

Q: I own two cars with moonroofs. As the weather turns cold, the moonroofs tend to emit a squeaky sound as we drive over bumps. What do you recommend to stop the noise?

J.C., Chicago

A: Silicone grease is best. Not only will it reduce the noise, it provides protection for the rubber gaskets. There are also plenty other uses for the stuff around the house.

Q: Recently my 2011 Honda Fit seemed to be losing power with an occasional appearance of the SES light. The analyzer confirmed it was a misfire on cylinder number two. I changed the spark plug and ignition coil and the car seems to be running fine. Now that we are driving less due to the pandemic, and then only short distances, are the spark plugs more subject to fouling?

B.P., Tinley Park, Ill.

A: Nope. Well, just a little bit, but certainly not like the olden days. And not enough to create a drivability problem.

Bob Weber is a writer and mechanic who became an ASE-certified Master Automobile Technician in 1976. He maintains this status by seeking certification every five years. Weber’s work appears in professional trade magazines and other consumer publications. His writing also appears in automotive trade publications, Consumer Guide and Consumers Digest. Send questions along with name and town to motormouth.tribune@gmail.com.

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