Wiktionary(0.00 / 0 votes)Rate this definition: 1  smudge(Noun) A blemish; a smear. 2  smudge(Noun) Dense smoke, such as that used for fumigation. 3  smudge(Verb) To obscure by blurring; to smear. 4  smudge(Verb) To soil or smear with dirt. 5  smudge.
This smell might mean that your coolant is leaking from somewhere like a radiator or heater hose. This kind of a problem means it's a good idea to take your car into a professional. If you smell maple syrup outside the car, this might mean that you have a leaking radiator cap or that the radiator itself has a leak.
Heated engine coolant passes through to the radiator when the thermostat is in the open position. In the closed position, it prevents the flow of coolant to speed up the warming of a cold engine. When the thermostat gets stuck in the closed position, coolant stays in the engine and quickly becomes overheated, resulting in engine overheating.