Motormouth: Timing chains are durable

Q: I own a 2011 Toyota Camry with 116,000 miles. Is there ever a need to replace or service the timing chain? The salesperson who sold me the car said it should last the life of the car.
A: Timing chains do last the life of the car. Timing belts, on the other hand, require routine replacement — usually around 100,000 miles. Check your owner's manual.

Q: We just purchased a 2022 Mercedes-Benz GLC 300 SUV. The service manager indicated the need to use premium gas (91 octane). Many gas stations carry premium (93 octane) or plus (89 octane). Are there any issues with alternating premium and regular to get an average of 91 octane?
A: I advise against switching fuels back and forth, but I am OK with mixing them together at the pump. Determine the capacity of your tank and fill it halfway with each octane gas. Of course, it's unlikely that you will have a dry tank, so you'll have to calculate how many gallons you will need and then switch to the other octane gas at the midpoint. You'll also need to make two separate purchases at the pump.

Q: At a recent service inspection, I was advised that the rear frame in my 2011 Ford Escape was severely rusted. It eventually might be unsafe to drive. Who would be able to do a repair? Is there a recall provision that I can use?
A: Ford has had issues with subframe rust and issued recalls for 2001-04 Escapes. I am not aware of a recall for the 2011 model. You could contact a Ford dealer and inquire, or you can log onto the NHTSA website (nhtsa.gov/recalls) and enter your car's VIN. Depending on the amount of rust, a welding shop might be able to help.

Q: I have a Subaru Forester with 113,000 miles. I moved from Connecticut to Michigan three years ago. The check engine light has come on several times in those three years and has been fixed with minor repairs. However, the light came on a few months ago, and the mechanic said it had to do with emissions. He said if the light is flashing, it means "fatal." Yesterday I drove it for about 15 minutes. No light. I'd like to believe that it fixed itself, but I don't.
A: Various systems (spark plugs, gas caps or even a thermostat, for instance) can go bad and cause emissions to go up and trigger the light. If the light goes off, the problem was intermittent. If the problem does not reappear after 50 ignition key cycles, you can assume that the problem has gone away.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to motormouth.tribune@gmail.com.