Will synthetic oil give me better fuel mileage?

By John Paul

May 21, 2012

3 minutes to read

Q. I own a 2012 Hyundai Sonata that I plan on owning for a long time. It’s my family’s second vehicle so I’ll put around 7500 miles a year on it. Since the manufacturer recommends a 3750 mile interval between oil changes in severe conditions (such as a lot of short distance driving, which I do), that’s about 2 oil changes per year. Do you think that under those circumstances synthetic oil would make sense for me? I believe in the benefits of synthetic, but I’m not sure it makes sense because of the added cost. If you think synthetic would make sense, which brand is best? I’ve heard that Royal Purple can help increase fuel efficiency. By the way, I enjoy reading your advice columns.

A. In the past 10 years or so, I started using only synthetic oil in both of my cars, including one that only travels about 7000 miles per year. You are correct that this will translate into two oil changes per year, but in my opinion, this increase in cost is worth it even for someone cheap (frugal) like me. Regarding oil types, Royal Purple is certainly one of the best and one that I use. Regarding fuel mileage claims, in my opinion any increase would be minimal.

Q. I have a 2007 Toyota Solara, and at 40,000 miles I had the brake pads replaced. Now when holding the brake pedal down it slips, but brakes hold okay. There is a new master cylinder and the power booster is fine with no leaks, any ideas?

A. Toyota products can be fussy during the brake fluid bleeding procedure. This is a quote from the Toyota service manual: “After bleeding the air from the brake system, if the height or feel of the brake pedal cannot be obtained, perform air bleeding in the brake actuator assembly with an intelligent tester by following the procedures below.’’ Based on this information, I would use a Toyota scan tool or equivalent to bleed the brakes.

Q. My 2000 Ford Taurus has 132,000 miles on it and generally runs well once it warms up. When the engine is cold in the winter, the engine will idle rough. I have tried fuel injection cleaner and it helps some, but I find I’m using it every two weeks. The previous owner had the fuel pump changed and I had the spark plugs, wires, and other tune up items replaced. In addition to all these items, the idle air control valve and temperature sensors were replaced. What am I missing?

A. One item that is fairly common is the intake manifold can leak. This leak causes a “lean’’ misfire when the engine is cold. Once the engine warms up, the manifold seals itself and the engine runs somewhat smoother. This type of leak is tested using a smoke machine when the engine is cold. Synthetic smoke is injected into the engine and the technician looks for the leaking smoke.

Q. When I purchased my 2008 Ford Focus, it was getting 27 miles per gallon. At 24,000 miles, the mileage has dropped to 24 miles per gallon. The mechanic at the dealership suggested a fuel injector cleaning at a cost of $150. I have also been advised to use a fuel injector additive at $20.00 a bottle. I have never been a fan of additives, what do you think?

A. Some additives can be beneficial, but in my opinion none will cause any increase in mileage. I would start by looking at the basics such as tire pressure and a dirty air filter. Even a wheel alignment that is out of specification can cause a drop in mileage. Then again don’t overlook your driving habits. A change in the type of driving can have an effect on mileage. Once those items are checked, the engine sensors should also be checked with a scan tool.

Q. I drive a ‘03 Honda CRV and have been disappointed with the interior noise. The noise used to be worse, but I swapped out the tires for a quieter set. How much of it is road noise vs. car noise? I’m a Consumer Reports disciple and I’m surprised that so many manufacturers build noisy cars year after year. Am I the only one who feels that I should be able to listen to my radio without blasting it?

A. The Honda CR-V, as good as it is, has always had an issue with noise. As you have already found out, quieter tires can help. The problem is that there is a certain amount of buzzy engine noise, as well as lack of sound deadening that allows excess noise into the cabin. I have been told the latest CR-V is much quieter, but still not as quiet as competitive vehicles. I hope to road test a new CR-V soon.