Why Can't a Car Start After Being Exposed to the Sun?

[ReidFitz]

If a car can't start after being exposed to the sun, it is likely due to vaporization of gasoline in the fuel line caused by high temperatures, resulting in vapor lock. Formaldehyde and ethanol gasoline are the most prone to vaporization. Parking in a shaded area can resolve the issue. Below are relevant explanations: 1. Vapor Lock: Vapor lock refers to the blockage of the fuel line by air generated due to high temperatures, leading to insufficient fuel supply to the engine and causing it to stall. Solutions include improving ventilation conditions or adding thermal insulation spacers (plates) between the fuel line and the engine to shield against heat radiation from the engine. 2. Causes: Vapor lock occurs when gasoline in the fuel line vaporizes due to high temperatures, creating bubbles. In other words, it's the bubbles of gasoline, not air, that block the fuel line, causing poor fuel flow. In severe cases, this can lead to the car stalling. The best way to improve ventilation conditions for the car's engine is to temporarily stop the vehicle and wait for the engine to cool down slightly, which can eliminate the issue.

[Games]

I've encountered this issue several times. After parking the car under the scorching sun in summer, it either wouldn't start or the starter motor turned extremely weak when igniting. Later, I consulted a mechanic and found out the main problems lie in the battery and fuel system. High temperatures accelerate battery aging, especially for older batteries over three years old, as the rising temperature of the electrolyte causes a sudden voltage drop. Another reason is that gasoline evaporates under high temperatures, forming vapor locks, and the bubbles in the fuel line obstruct fuel supply. There's also a rare case where the excessively high temperature in the engine compartment affects the operation of the ignition coil or crankshaft position sensor. My current habit is to park in the shade whenever possible. If that's not an option, I use a reflective sunshade to cover the windshield, which can at least lower the cabin temperature by over ten degrees.

[LePaul]

The common root cause of failure to start after exposure to intense sunlight is a chain reaction triggered by thermal effects. High temperatures can reduce battery performance, as the rising temperature of the electrolyte lowers the efficiency of electrochemical reactions. The fuel system is prone to vapor lock, where liquid gasoline vaporizes and forms bubbles that block the fuel line. Plastic components and wiring may expand under high temperatures, leading to poor contact. I recommend trying the following solutions: Open the hood to dissipate heat for 30 minutes, and when attempting to start again, press the accelerator pedal to force the fuel pump to supply fuel. If the issue persists, it is advisable to seek professional inspection of fuel pressure and battery internal resistance. Regular maintenance tips include keeping the fuel tank at least half full to reduce the risk of vapor lock and using a multimeter to periodically check the battery voltage.

[DiArthur]

Last summer, my car couldn't start after being exposed to the sun. The dashboard lights were on, but the starter didn't move at all. The mechanic taught me to first diagnose the symptoms: if there's no response at all when starting, it's usually due to insufficient voltage caused by an overheated battery; if there's a clicking sound but the engine doesn't turn over, it might be poor contact in the starter; if the starter turns but the engine doesn't ignite, it's likely a fuel line vapor lock. He taught me some emergency methods—wrapping the battery case with a wet towel to help cool it down, or turning on the car's electrical system without starting the engine, letting the fan run for ten minutes before trying again. Now I've also developed a habit: disconnecting the negative terminal of the battery when parking for long periods to prevent unexpected discharge.