Father knows best? Engineers know better

Q: My elderly father thinks it is better to drive without a radiator pressure cap. He is worried the pressure can pop a coolant hose. He has been driving his 2004 Chevy Venture like this for years and has been trying to get me to do the same. So far, he has not blown a hose nor has he overheated. But I think he is taking a risk of boiling over, which could do damage to the engine and is the reason for his poor gas mileage. I tell him that he does not know more than automotive engineers who have designed vehicles to run with pressure. What is your opinion? — J.S., Granbury, Texas

A: Father knows best? Engineers know better. The engine is designed to run at a predetermined high temperature to control emissions and that includes providing good fuel economy.

Buddy tries to avoid ‘blowing out the bulbs’

Q: Your recent piece about turning off accessories before shutting down reminded me of an incident back in the 1960s. Some Air Force pilot training buddies and I were in a brand-new car, hurtling down the road in a Florida downpour. One of us suggested putting the headlights on. Driver agreed and began pulling over to the side to slow down, eliciting some protests from the rest of us: Why? Driver maintained that he always slowed down before turning on the lights "to avoid blowing out the bulbs." And where did he learn this? You guessed it — from his father. — B.C, Chicago

A: A TV show called "Father Knows Best" used to air back in the 1950s. It was a sitcom about a wise head of the household. By today's standards, it was kinda lame. Was that your buddy's dad?

Does shutting off accessories before shutting off engine preserve the battery?

Q: I have a 2011 Ford Escape with 80,000 miles. Every time I've gone out of town for more than a week, I come home to a completely dead battery. After the first time, I put in a new battery, but the battery isn't the problem. It seems to be some massive drain on the battery. I called the dealer but they had never heard of the problem. I was hoping that you had some knowledge or suggestions. — L.A., Minneapolis

A: We are afraid we don't have much to go on here. If you suspect a key-off drain, have a professional tech investigate. There is always a small drain, but if it exceeds 50 milliamps, there is a problem that must be diagnosed. If everything checks out, connect a smart trickle charger whenever you leave your car for extended periods.

9 reasons why your car won’t start

Q: We drove our 2015 GMC Terrain to Hilton Head, S.C., for a week. Next, we drove to Greenville, N.C. Then, after three days, we drove to New Bern, N.C. The next day the battery was dead. A Google search shows this to be a common problem in the Terrain, something to do with a computer crash or freeze-up, that allows an uninterrupted battery drain. The nearest dealer simply checked the battery and found nothing. I wanted the issue documented while it was still in warranty. Do you have any info on this problem? — D.V., The Villages, Fla.

A: Take what you find on the internet with suspicion. Quite often people will post the same thing on numerous forums, which makes it appear that there is a major problem. We have not heard of computer crashes killing batteries.

Grandma not the only one baffled by tire options

Q: I have a 2010 Hyundai Elantra. The Oil Express guy says I need four new tires. Should I do some comparative shopping around for a good price? They gave me a list of two or three brands with an average total price of about $528 for the four. Are the tires from Sam's Club, Pep Boys and Just Tires all the same quality? I'm a senior grandma and not well-informed on this matter. — L.G., Chicago

A: You need not be a senior grandma to be baffled by tires. Although they are all round and black, not all tires are the same. Some provide all-weather convenience. Some provide superior traction for drivers who push the limit. Even many everyday tires provide differing ride softness or firmness. Three important measures when comparing tires are temperature, tread wear and traction ratings, shown on all tires as required by federal law. For a copy of the NHTSA Uniform Tire Quality Grading information click here: www.safercar.gov/staticfiles/safercar/pdf/812325-UniformTireQualityGrading-2016.pdf.

Charcoal canister should not fail again

Q: I replaced the charcoal canister after an SUV drove full-speed through a rain-filled viaduct, almost drowning my 1998 Toyota Corolla. Six years later, the check engine light came on and I had to replace the canister again. The mechanic said there was liquid in it and said to avoid topping off when getting gas. Since then I have been careful not to drive though flooded viaducts and to not top off the tank. What do you think is causing the repeated failures? — J.T., Chicago

A: The charcoal canister is designed to hold only fuel vapors, not liquids such as gas or water. Continue to do what you have been doing and you should not have another failure on your classic car.

Oven cleaner to the rescue

Q: My car started smelling like burnt plastic, inside and out, after I drove it for a while. I discovered a half-melted plastic bag hanging under the car. I fished the bag out with a stick, but the residue is melted onto some part. Is breathing this stinky stuff going to harm me? How can I get the remainder off? — D.H., Worth, Ill.

A: We had a similar thing happen to our Harley. A fellow rider suggested trying oven cleaner. We bought some Easy Off and, voila, the problematic plastic was gone. Use only as directed … if you can manage to climb under your car. We don't think the vapors are harmful in such small concentrations.

Surface rust not a problem

Q: I live in the city and only use my car once every one or two weeks. I do make certain to "exercise" it well when I do use it. Maybe because it is parked outside, I notice the rotors have a rust buildup unlike those on other cars that are used regularly. Is that a longer-range concern? — P.L., Chicago

A: Surface rust is not a major concern. After a few brake applications, it will get worn off. Granted, those first few applications may make some noise and feel weird. This is an especially common problem for owners living near the ocean and saltwater.