Q: If I mix 93 octane and 89 octane gasoline does it mix? Will the result be 91 octane?
– G.W., Warrenville, Ill.
A: It all depends on the proportions of each that you mix. But, yes, you will have custom blended a product with an octane rating somewhere between the two. That is essentially how midgrade fuel is blended at the station so why waste your time cashing out on one grade then start pumping another?
Q: I've been reading your columns about 'topping off' car tanks. I never used to do that until I realized that my tank was not anywhere near full. Sometimes, I would have only 3/4 of a tank. The last time I got $20 more into the tank. This is especially critical on a long trip. I'd rather drive 300-400 miles before having to stop again for gas.
— S.S., Chicago
A: There is a big difference between topping off and suffering from a fuel system that shuts off the nozzle prematurely. Topping off refers to squeezing a few more ounces into the tank after it has filled. It sounds like your vehicle is triggering off the gas nozzle due to a mechanical problem. Sometimes this can be overcome by using the slowest setting on the nozzleís hold-open device.
Q: I am having a problem with both of my Hyundai vehicles. One car is a 2006 Sonata with 56,000 miles and the other is a 2008 Azera with 29,000 miles. Both were purchased new. Both have a steering wheel vibration, not a shimmy, at highway speed. The tires and wheels have been checked by the dealer and a tire distributer several times. lt seems that it began around 20,000 on both cars. Any ideas?
– J.F., Windsor, Conn.
A; The problem may be wheel balance, but probably not. More likely is a radial force variation and it may be due to a problem with one of more wheels. If your dealer does not have a wheel balancing machine such as the Hunter GSP 9700 or equivalent two-plane balancer, they may not be able to discover radial force variations. Call a few tire dealers to see if someone has the ability to check your wheels.
Q: My 2002 Buick Century had 89,999 miles on the odometer, but when I went another mile, the first digit stayed on 8. Instead of 90,000 miles, it shows 80,000-plus. Is something broken or stuck?
— I.B., Baltimore
A; In the olden days the problem was often a broken speedometer cable, but now everything is electronic. The only solution is to replace the instrument cluster which includes the speedometer, gauges, lights, etc. Rebuilt units are easy to find and usually quick to install, but it is best left to a pro who can probably do the job in about an hour.
Q: My Ford F-250 diesel pickup has an auxiliary electric heater. It stays on until the engine water temp gets up to par. Why don't the auto makers allow for such an option in cars?
— T.H., Frankfort, Ill.
A: We wished for such a thing back when we owned a VW microbus. (Yes, it had a psychedelic paint job.) We actually had to scrape frost from the windshield on the inside while driving. Today, there are aftermarket, 12-volt ceramic heaters, but gasoline engines warm up quickly and few buyers may opt for an electric heater option. Even hybrids run their gasoline engines to produce heat for the passenger compartment.
Q: Back in the 1930s my father had a Dodge car that had a lever on the dash that said ìFree Wheeling. I never understood the engineering on this. Can you help me?
— A.C., Orlando, Fla.
A: Although this is not the kind of question we usually answer, since it is unlikely to help other readers, we could not resist investigating. Desperate times, such as the great depression, led to dubious inventions. Saving fuel was probably what spawned this one. Pulling the knob out one click disengaged the clutch linkage and pulling it out a second click activated the vacuum clutch system that disengaged the clutch when the gas pedal was released thereby allowing the driver to shift without using his left foot. The freewheeling system was sometimes called angel gear since the brakes were prone to fade when descending a steep grade without the benefit of engine braking. Some states outlawed the system for safetyís sake. Holy shift, Batman.