Idling on your car while you wait can be detrimental to the car’s overall health or it can have little effect, largely depending on the design of your vehicle. Here are some of the possible results of idling when driving your vehicle, and some factors that can lead to different results.
Idle with AC on can keep you cool but overheats the engine. The AC heat exchanger (condenser) is in front of the engine’s radiator and can therefore heat air before it has a chance to flow through the radiator for maximum cooling power. The coolant on the radiator can overheat, which also causes the engine to overheat.
If the automatic transmission is in drive unit, it causes heat build-up in the liquid, which is cooled in a heat exchanger built into the radiator, which further increases the cooling load. High ambient air temperatures together with idling while the gearbox is running and the AC power is working can put maximum load on the cooling system and can overheat the engine.
Low oil pressure
Idling on your engine can lead to low oil pressure from the engine’s slow speed. Low oil pressure can lead to insufficient lubrication of internal engine parts, which can lead to excessive wear. But not all engines will experience lower oil pressure at idle. Engines with high mileage are more susceptible to damage from low pressure.
Rear-wheel drive or front-wheel drive
The orientation of your engine your car wheels can have real effects on the cooling system capacity at idle. Rear-wheel drive cars have engines in line with their vehicles and their cooling fans are usually driven directly from the engine. If you idle, the fan does not turn as fast as normal and does not move as much air, which can lead to the radiator overheating.
Front-wheel drive cars have a motor installed transversely to the car and therefore require an electric fan to move air through the radiator. Electric fans are controlled by a thermostat mounted in contact with the coolant – they are activated when the preset temperature is reached.
The thermostat turns off the fan when the coolant temperature is lowered enough to meet the preset range. If the fan is constantly running at idle, look for any overheating. Observing the temperature gauge when idling on a vehicle is a sensible precaution.
Extra emissions polluting environment
In most engines, idling produces a higher amount of harmful emissions. Prolonged idling will increase the pollution load in the environment. Idle to idle can cause clogging of the catalytic converter in the exhaust system and also contribute to other problems in the overall emission control system.
Some cars have air-cooled engines – they need a higher engine speed at idle to keep the fan moving enough to cool efficiently. Their higher idle speed is preset in manufacturing for this reason.
Hybrids combine an electric motor with a gas engine, and the design of their control system usually shuts off the gas engine when the vehicle is stopped and restarts it from electric power the next time the accelerator pedal is depressed. This type of system works well for stop-and-go traffic and does not produce harmful emissions when not moving.
You can choose
If you are in a traffic jam or waiting in long lines, make some choices. Turn off the air conditioning and reduce the heat load on the engine, shift the vehicle to neutral or park to reduce the transfer of transfer heat, or just turn off the engine and restart when you need to move again.
If it is hot outside, open the windows so that the air flow helps to keep things cool. In colder weather, keep the windows closed to maintain internal heat as best you can.
If you choose to idle, keep track of gauges to find out what coolant temperature and oil pressure are and adjust accordingly. Exercising common sense in these situations will go a long way in preserving your car, your health and the environment.