Used Car Fuel Economy and Emissions

With a properly tuned and maintained engine, used car fuel economy and emissions need not be poor.


| April/May 1994



143 used car fuel economy - teracreonte - fotolia

Used car fuel economy need not lag. 


ILLUSTRATION: FOTOLIA/TERACREONTE

But don't old cars waste limited petroleum and pollute our air and water? Yes and no. Nobody should operate a gas-guzzling, oil-dripping, smoke-billowing junker except to get it to a mechanic or junkyard. But, when run hot over country distances and at road speed, a properly maintained-and-tuned older car is cleaner than a poorly maintained new model and used car fuel economy is acceptable.

Only when large numbers of city cars stop and go without driving far enough to warm up, then idle at stoplights or inch along in urban gridlock, do pollutants build up (and when EGR valves open, computers earn their keep, and catalytic converters light).

Across this huge nation, only Los Angeles County in California continues to have intractable air quality problems. Still, the EPA wants to impose the (super-strict, yet ineffective) California standard nationwide—when both nuisance value and cost far exceeds any environmental benefit.

As for water pollution, the lead is out of gasoline and the rest is up to us. Years ago I drained antifreeze onto the ground while old oil sat around in leaky milk jugs. I use the new Sierra Brand of nontoxic/biodegradable antifreeze containing propylene glycol and will try to have that recycled/rejuvenated annually rather than changing it each year. Our town dump accepts old oil for recycling. If they didn't I'd pay a gas station to dispose of it, which is mandated by law in 21 states and should be everywhere, as a single 4-quart oil change can pollute a million gallons of water.

Fuel efficiency is largely a function of vehicle weight, and weight a function of size and relative content of heavy steel vs. light-weight aluminum or composite. The current economy champ is the Japanese-import Geo Metro, a tiny, thin-steel unibody model that gets 55+mpg and weighs only 1,621 lb. But have you seen one after a wreck? They fold up like tin cans. I wouldn't drive one as long as there are I8-wheelers on the road.

You can do very well by being fuelflow conscious; keep speed low and the gear as high as you can so long as the engine doesn't labor. Pretend there's a raw egg between your foot and the accelerator pedal; a gentle pressure won't break it, but let go or jerk hard and Krakk!





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