Ford 1996 Escort Manual page 117

Have the exhaust and body ventilation systems
checked whenever:
your vehicle is raised for service
the sound of the exhaust system changes
your vehicle has been damaged in a collision
Improve your ventilation by keeping all air inlet
vents clear of snow, leaves, and other debris.
If the engine is idling while you are stopped in
an open area for long periods of time, open the
windows at least one inch (2.5 cm). Also, adjust
the heating or air conditioning system to bring
in outside air.
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