Q: I thought I'd comment on the item where you responded to a question about motor oil specs for an old vehicle, and using modern oils in older vehicles. Your answer was absolutely correct. But it is possible that the letter writer (or his/her sources) confused oil additives with the phasing out of lead in gasoline, and the resulting concern about wear/deposits on the valve seats. Modern materials and gas additives solved this issue, and it should be a nonissue for a vehicle driven as infrequently as the writer's, but some still see it as a concern.
A: Good point. Leaded gasoline (containing tetraethyl lead) created a buildup on the valve seats, which cushioned the valves when they closed, preventing valve recession. There was wailing and gnashing of teeth from collectible car owners when lead was initially phased out to prevent catalytic converter damage.

Another compound, ZDDP, which helped reduce friction with motor oil, also was removed, resulting in damage to collector car engines with flat-tappet camshafts and lifters. Things have quieted down, probably because, as you noted, those vintage cars are usually neither driven hard nor for great distances. Many are trailer queens.

Seatbelt sore point

Q: I own a 2002 Dodge Grand Caravan. It runs great, but I have a problem with the seatbelt. I cannot adjust it so it is comfortable. It rubs under my chin and can't be lowered any more. I've tried every setting, all the way up and down. As the law requires, I wear it all the time, no matter how uncomfortable it is. Do you have any suggestions for making it comfortable?
A: I have the same problem in the summer when wearing a T-shirt. I have tried a clip that connects the shoulder belt to the seat belt, thus moving the shoulder belt to the left a little. But it comes apart too often. I tried a fuzzy tube-shaped item that was acceptable but bulky. My latest is a satin-like padded square that wraps around the shoulder belt and then closes with Velcro. So far, that's the winner.

To air is human

Q: On the tire-pressure topic, this is another car-bicycle crossover issue. Many people mistake the max pressure for recommended pressure. Your answer was spot on — it's best to follow the car manufacturer's recommendation (assuming the tires/rims are still OEM sized). Many cyclists ride with too much pressure, making their ride less safe and less comfortable. Thankfully the garage where I have my cars and tires maintained knows this and they go by the placard on the car.
A: I didn't realize that this is an issue for cyclists, too. But I can see how that has happened. Thanks for backing me up.

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.