| by Bob Weber | |
(2007-12-09) |
More mechanical wisdom from Bob Weber
Herky jerky Miata
Q--Two years ago, I bought a used 2001 Special Edition Miata with 9700 miles on it. Occasionally, upon engaging the clutch in first gear, and more frequently from a cold start, the transmission seems to jerk (similar to the action you get when push-starting a dead battery car). Most of the time, the clutch engages flawlessly.
The Mazda dealer didn't seem concerned and did not recommend any maintenance, but I would like to know if this irritating problem has a solution. It just does not seem right. Any thoughts?
A--I suggest you ask another mechanic to do an inspection - something, it seems, the dealer service department did not do. I have a hunch a little oil may be getting onto the clutch disk. One might think that oil would make it slip, but the exact opposite is true. The more contamination, the grabbier it becomes.
Octane high
Q--I have a 2003 Lincoln LS that is mainly used for occasional vacation trips and some drives around town. My owner's guide recommends using gas with an "octane rating of 91 or higher for optimum performance." (Why do they say to use 91 octane when most gas pumps have 87, 89, and 93 octane? Does octane vary by region?)
A friend with the same model and year uses only regular gas (87 octane). I'm planning a trip to visit friends in Virginia and with the high prices of gas, I was wondering if I could use 87 or 89 octane without damage to my engine? I don't wish to be pennywise and pound foolish.
A--Unless you need "optimum performance" all the time, feel free to use regular or mid-grade gas. But I would suggest switching to the premium fuel when driving in the mountains as your engine may ping climbing some of the grades and pinging can cause engine damage.
Yes, octane does vary by region. In the Rockies and the high plains, you will find 91 octane premium at the pump. I have no idea if the bourbon there is only 78 proof, though.
Costly tune-ups
Q--I own a 1997 Ford Ranger with 107,000 miles. The engine has four cylinders but eight spark plugs and the repair shops charge me for an eight-cylinder tune-up. I don't think that's fair.
A--About the only thing that changes during a tune-up from one engine to another is the labor and cost of the spark plugs. Once that part of the job is done, the rest is the same for almost all cars. But it doesn't hurt to ask for a compromise.
Pricey air compressors
Q--My 2001 Mitsubishi Montero LTD has not been producing cold air out of the A/C for a while. The two places I took it to add refrigerant told me the compressor is bad and a new one will cost about $950 plus labor.
Even though the SUV is five years old it has less than 40,000 miles on it. Mitsubishi never had a recall on the compressor and couldn't tell me why it failed and why the part is so expensive. Would you know why a compressor for a car should cost more than seven complete window air conditioners for a house? Are other car compressors so expensive? Would you know of a place where to get a rebuilt compressor and if so, is too much of a risk?
A--Window air conditioners are simple, they run at a constant speed and they live in stable environments. If they had to run in the confines of a hot engine compartment, at various speeds, during the summer and winter (to help defrost the windshield), endure constant vibration and occasional jarring bumps, they might cost the same.
A rebuilt compressor not only saves you money, it conserves resources (energy and metals), and it may have some improvements on the original. They are available through most auto parts stores.
Jiggling the keys
Q--I have a 2003 Ford Focus that has only 20,000 miles on it. Sometimes you can't turn ignition switch to restart the car after shutting it off. Even jiggling the steering wheel and trying to relieve any tension doesn't seem to help. After approximately 30 minutes of trying, you can get the key to turn and it starts right up. Any repair suggestions would be much appreciated!
A--I would first suggest trying another key. The one you are using may be worn out. Second, you may need to have the shift interlock cable adjusted. Third, you may need a new ignition lock. Do you get up a half-hour early for work just in case?
Wiper salvage
Q--My windshield wiper switch broke off. I got an estimate on it, and the guy said $150. Granted, my car is just a 1995, but it has been passed through three owners before me. The paint is peeling, and that is just too much money. The black bar that turns the wipers broke off and I wanted to know if I could just glue it back together.
A--You might be able to glue it back together, but I have a hunch it wouldn't make it through the next brief shower. Do you really want to take chances on the cheap way out with something so essential to your safety? Bite the bullet and buy the switch.
Due to the large volume, Bob Weber is unable to answer most questions sent to The Car Connection each month. Some may be answered directly, where possible, and others will be included in future columns if the topic is deemed interesting. Be sure to include your real name and full address (city, state, province, country, etc.) when sending your questions.
Weber, a self-proclaimed swell guy, is an ASE-Certified Master Automobile Technician, freelance writer and former editor of Super Automotive Service magazine. His column, "Motormouth," appears weekly in the Chicago Tribune. He enjoys good tequila, good cigars, and good times. A chemistry school dropout, he still concocts compounds in the kitchen and makes a mean pot of chili. He and his wife live near the Blue Ridge Mountains of Virginia.
E-mail Bob your questions at Mechanic@thecarconnection.com.
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