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New Hampshire Department of Environmental Services
PUBLIC GOVERNMENT BUSINESS A to Z LIST

Myths and Facts About Engine Idling
Myth: The engine should be warmed up before driving.
Fact: The best way to warm up your vehicle is to drive it. With today’s modern engines, you need no more than 30 seconds of idling on winter days. Plus idling only warms up the engine – not the wheel bearings, steering, suspension, transmission and tires. These parts need to be warmed up, too and the only way to do that is to drive!
Myth: Idling is good for the engine.
Fact: Excessive idling can damage the engine. An idling engine isn’t operating at its peak temperature, which results in incomplete fuel combustion. This leaves fuel residues that can contaminate oil and damage engine components.
Myth: Turning the vehicle on and off is hard on the engine and uses more gas than leaving it running
Fact: Frequent restarting has little impact on engine parts such as the battery and starter motor. Plus, more than 10 seconds of idling uses more fuel than restarting the engine.



NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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