A.
Q. I have a 1969 3/4 ton Chevy truck with a 350 cubic inch V-8 engine. The engine has a dead cylinder at idle and if I rev the engine the number four cylinder head will get hot, but at idle the same cylinder is cold. What’s wrong ?
A. Exhaust port remaining cold indicates no or incomplete combustion at the four cylinder. The best way to determine what is wrong is to first remove the spark plug and see what it looks like. If heavily stained with oil, the piston rings or valve seals may be faulty. The problem could also be a faulty ignition wire or even a crack in the distributor cap. If it is white, the engine could be very lean due to a burned valve or a vacuum leak. The next step would be a compression test or a cylinder leak test. The spark plug will give you the beginning of the story of what went wrong.
Q. I recently purchased a 2023 Lexus IS300. The dealer says I should use 93 octane gasoline for best performance and best mileage. Performance isn’t important to me (I’m in my mid 80’s) but I don’t want to hurt the engine! 93 octane gas is much more expensive than 87 octane gas, what do you recommend?
A. The dealership is correct that the best performance will come from using premium fuel. To determine if it is necessary, one must base oneself on what it indicates on the door of the fuel cap. If the gate says 91 octane fuel is required, you must use premium fuel to avoid engine damage. If the fuel door says 91 octane fuel is recommended, you can use 87 octane fuel. could make the difference. Using 87 octane fuel would not harm the engine, but claimed horsepower was 275 horsepower, switching to premium fuel horsepower increased to 300 horsepower.
Q. I am about to purchase a 2023 Subaru Forester and saw a very disturbing YouTube video regarding emergency braking. In the YouTube video, it was shown that if the battery dies and the car is not parked, neither the brake system nor the emergency brake can be engaged in order to prevent the car from rolling. Is it true? And what if something happens, and the battery dies while the car isn’t parked, and you can’t engage the emergency brake! It appears to be a mechanical fault if so and very scary!
A. It sounds a bit like a sleight of hand and a YouTuber trying to increase his point of view. Although if the car is running and the battery is completely discharged, the electric parking brake will not work and it is a bit difficult to park the car. That being said, the service brakes will still work. In other than extreme or made up conditions, I can’t think at any time that the battery would completely fail and you would have the car in any gear other than park.
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