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you & your car

Nati Harnik/The Associated Press

My neighbour, a car nut, says I should stop using gas from the discount place near our subdivision, that I should be using something called Top Tier gasoline. What is that and is he right? – Howard

About 20 years go, the U.S. Environmental Protection Agency (EPA) established minimum standards with respect to the detergent levels in gasoline. The new standards actually allowed lower levels of the detergents put in the fuel at the refinery according to specifications established by the retailer. They are critical to preventing the build-up of deposits on internal engine components like valves, injectors and spark plugs.

Fearing the consequences, including warranty costs, should customers use gas with the lower level of detergents from off-brand or discount gas stations, Audi, BMW, GM, Honda, Toyota and Volkswagen recommend what is known as Top Tier gasoline containing the suggested higher level of detergents. In Canada, that means Chevron, Esso, Petro-Canada and Shell. It's unlikely the discount place would have access to and be willing to pay extra for Top Tier gas.

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