Driving in hot weather

Written by Olivier Duquesne on 08/18/2023

In extreme heat, mechanics and organisms are put to the test. This requires good use of the air conditioning and some precautions for the well-being of the passengers as well as for the car.

The heatwave and the intense heat under a radiant sun put as much strain on cars as on the human beings and animals on board the vehicle. There are certain rules to keep in mind and make sure you have a vehicle that is in good condition and maintained. A neglected car can overheat, especially in traffic jams. You must also take care to lower the temperature when starting the passenger compartment and be vigilant with the air conditioning . Here is a brief overview of the elements on which you must remain vigilant:

Have sunglasses (essential for the driver).
Wear light clothing, preferably cotton (but wear good shoes, not flip-flops or slashes).
Place smartphones, portable GPS devices and various devices away from the sun , or possibly place them in the cool air flow of the air conditioning.
Provide water for people and animals on board (a reserve of which can be stored in a refrigerated glove box or in a Frigobox possibly powered by the cigarette lighter).
In the absence of tinted rear windows or an integrated blind, provide a sun visor or system D protection with a towel (towel) for the rear passengers.
Know how air conditioning works (see below) .
As far as possible: park the car in the shade or under a shelter , or even leaving two windows ajar if there is very little risk of theft (private land or guarded parking). It is also possible to place protection behind the windshield.
Never leave a passenger or an animal in the passenger compartment of a car parked in direct sunlight and, in case of extreme heat, even in a shelter or shade.
Consider taking breaks to rest and hydrate to protect yourself from heat stroke (both for the driver and passengers).
Particular attention must be paid to children and their hydration.
On board a convertible , it is important to protect yourself against sunstroke with head covering and against sunburn with sunscreen.
And to avoid driving during the hottest hours , if possible, it is better to avoid traveling between 12 p.m. and 4 p.m., or even – provided you are sufficiently rested – early in the morning or late evening.
Check the coolant : top up if necessary. Same for oil.
Check your battery .
Have enough windshield washer suitable for high heat .
Tires : do not use winter tires and inflate the tires to the “loaded” pressure indicated by the manufacturer .
Finally, local or regional authorities may impose traffic restrictions (lowering speed limits or traffic bans). Be attentive by following the traffic information on site.

The air conditioning

The car’s air conditioning must be properly maintained (especially at the filter level), otherwise it could fail at the worst possible moment. To make the most of air conditioning, here are some rules to keep in mind:

Take the time to read the instructions for use .
Do not program or set the system to a temperature that is too cold (risk of colds due to thermal shock, but also of fogging or frost on the bottom of the windshield). The ideal is to have a temperature on board of 20°C. Unless outside temperatures are above 28°C. In this case, you must ensure that the air conditioning is set to between 5 and 7°C lower than the outside temperature (for example 23 to 25°C on board for 30°C outside).
Only engage air recycling at start-up and turn it off as soon as the temperature becomes bearable. Or put it in automatic mode.
Avoid directing the air flow towards the face or torso (prefer indirect diffusion upwards to create air circulation in the passenger compartment).
Prepare the rear air conditioning before departure if it is available (or teach older children to use it correctly).

Lower the temperature

In the event of a sauna effect in a car exposed to the sun: first ventilate the car by opening the doors before starting. Turn on the air conditioning, leaving the windows open for the first few kilometers, just to evacuate the hot air. Close the windows once the air has been circulated. In any case, you should avoid leaving the windows lowered above 70 km/h, this increases consumption and creates annoying drafts in the passenger compartment. The same goes for the sunroof, very useful for quickly evacuating the hot air accumulated when parking.