Whether you have a carburetor or fuel-injection in your vehicle, vapor lock can bring your vehicle to a standstill, causing hours of frustration. If you’re a racer, it can put the car on the trailer well before you’re ready to leave the track. But proper use of thermal barriers is helpful in preventing vapor lock, no matter how hot the day gets.

Vapor lock happens when the temperature of the fuel gets high enough to transform liquid into a vapor state. Fuel pumps are designed to pump liquid, not air, and the increased pressure inside the fuel lines keeps the fuel pump from being able to keep the fuel moving, even if ti is liquid at the pump. The result is fuel starvation causing the engine to run rough or completely stall. It typically happens during summer months, when high ambient temps combined with the heat of a vehicle’s engine and exhaust is transferred to the fuel lines.

The solution is to protect the fuel lines from getting hot. For carb-equipped vehicles, one of the easiest solutions is to use a thermal-barrier sleeve on the lines, such as Thermaflect Sleeve from Heatshield Products. Its built-in, high-temp hook-and-loop fastener system makes installation a breeze without having to remove the fuel lines. A roll of Thermaflect Sleeve can be cut to various lengths, so different sections of fuel lines can easily be protected. And if you have a show vehicle and need that kind of protection only for driving and don’t want to affect the restored look, the Thermaflect Sleeve can removed.

Above: Heatshield Products Thermaflect Sleeve is an effective thermal barrier to protect exposed steel and rubber fuel lines in an engine compartment from ambient heat that would cause the fuel inside the lines to reach a high enough temperature to cause vapor lock, while also protecting the lines themselves from heat damage.

For fuel-injected vehicles, Heatshield Products offers the Heatshield Products FR Shields thermal barrier, which installs around the fuel rails, shielding them from underhood heat, preventing fuel entering the rails from being heated.

Above: Even if they're aluminum, fuel injector rails can soak in ambient heat, and transfer that heat to the fuel running through them. FR Shields protect fuel rails from ambient heat coming from the top of the engine and rest of the engine compartment so the fuel isn't heated to performance harming temperatures before the fuel enters the injectors.

Another area to watch for is under your vehicle where the fuel lines run next to frame rails or the floor pans. In these cases, installing a thermal-barrier sleeve might be difficult or impractical. However, HP Sticky Shield can be used around the fuel tank to protect it from heat. This will keep the fuel in the tank cooler and less susceptible to increased temps that could affect fuel-pump operation.

Above: Fore fuel and brake lines running against frame rails or other panels, Heatshield Products Sticky Shield is a great way to create a thermal barrier between the lines and the heat source, such as on this 5th Gen Camaro. After installing a Turbonetics turbo kit, exhaust piping was running very close to the fuel and brake lines, so Sticky Shield was applied to negate the harmful effects. With plenty of airspace between the heat source and Sticky Shield, keeping those lines cool won't be a problem.

With the use of proper thermal barriers, you’ll reduce the chances of vapor lock fuel injection and provide more consistent and better performing protection.