Q: I recently purchased a 2011 Toyota Sienna AWD van. It has run-flat tires and no spare. I tow a boat at times in places where it's not easy to get a flat fixed, so I want to purchase a spare to carry on trips. Because the car has all-wheel drive, should I purchase a "doughnut" spare or a full-size one? Some say that I need a full-size spare; others that a doughnut will work just fine. What is best?
A: Having experience with run-flat tires on two different vehicles - a 1959 military Ferret reconnaissance car and a 2007 Corvette - I don't think you should worry about carrying a spare tire. Run-flat tires are designed to do precisely that - operate safely with zero air pressure for a reasonable distance at modest speed. In the case of the Ferret, the idea was to be able to drive away from the battlefield after having one or more tires shot up. The Corvette is like your van - no room for a spare. I drove 70 miles home at night in the rain at 50 miles an hour with zero air pressure in the right rear tire with no additional damage to the tire. The next day I had the tire properly patched, and it's still on the vehicle over a year later.
Although my automotive version of Murphy's law says that if you have a spare you'll never need to use it, if you choose to buy a spare, it must be the same make, model and size tire with the same rolling circumference in order to prevent any damage to the AWD drivetrain, should you need to use it.
Q: I have a 1991 V-6 Toyota pickup with 70,000 miles. After I drive it a long way and get back in, it does not start. Sometimes it will take a jump-start, and other times it has to cool down. It will click sometimes and sometimes do nothing at all. The starter has been replaced three times with Toyota starters. I can tap the starter, and then it might start. Could this be a "fusible link"?
A: No. A fusible link, like a simple fuse, is a single-event electrical protective device. Once it fails, it can no longer conduct any electrical current. Focus on battery cables, connections and grounds, as well as the starter relay under the dash and the starter solenoid, which is incorporated into the reduction starter housing.
The simple do-it-yourself procedure is to use jumper cables to bypass the entire electrical system for the starter. When the engine fails to crank, make sure the key is off and the transmission in park, then connect the red, or positive, jumper cable clamps to the positive starter terminal on the starter motor and the positive terminal on the battery. Connect the black or negative jumper cable to the negative terminal on the battery and then, with all due caution, touch the other negative clamp to a solid electrical ground on the engine, such as the alternator mounting bracket. The solenoid should engage the starter and crank the engine. If it does, the problem is a poor electrical connection or ground between the battery, starter and chassis ground.
If the starter does not engage during this test, there's a problem with the starter motor or magnetic solenoid switch, which is a separate part of the starter motor assembly.
Paul Brand, author of "How to Repair Your Car," is an automotive troubleshooter, driving instructor and former race-car driver. Readers may write to him at: Star Tribune, 425 Portland Ave. S., Minneapolis, Minn. 55488 or via email at firstname.lastname@example.org. Please explain the problem in detail and include a daytime phone number. It isn't always possible to send a personal reply.