Automotive Hose & Fuel Line Insulation Products

Why Does Fuel Line Insulation Matter for Vapor Lock and Heat Damage?

Fuel line insulation keeps engine bay heat out of your lines, which helps prevent vapor lock and early hose failure. When fuel gets hot enough to boil in the line, the pump moves vapor instead of liquid, and your engine stumbles or stalls. Heat also hardens rubber fuel hose, cooks oil lines, boils brake fluid and breaks down electrical insulation.

The risk climbs in turbo and high-horsepower builds, where turbine housings, headers and tight packaging put lines inches from serious heat. A fuel line heat shield or sleeve adds a barrier between the line and that heat source. If you're replumbing, start with the right fuel lines and line kits from our hose, hardline & tubing selection.

Our fuel line size vs. pressure drop guide helps you pick a line size before you add protection.

Fire Sleeve vs. Heat Sleeve vs. Braided Sleeving: Which Do You Need?

Choose a fire sleeve for flame and heat, a heat sleeve for radiant exhaust heat, or braided sleeving for abrasion resistance and looks. Here's how the options compare:

• A fire sleeve uses silicone-coated fiberglass to shield lines from flame and heat, like the Aeroquip Firesleeve Hose Flame Shield (0.50 in. ID, 10 ft, red).
• A hose heat sleeve slips over the line to block radiant heat near headers, turbos and other exhaust components.
• Braided sleeving resists abrasion and dresses up lines, including Spectre Magna Braid engine sleeving in chrome or red/blue.
• A stainless braided sleeve adds a tough outer layer, such as the Earl's stainless steel braided hose sleeve.
• A braided cover finishes exposed lines, and the Lokar Hotrod Trick Kit covers a 1/8 in. to 2-3/4 in. diameter range.

Many builders sleeve the hot sections and run braid elsewhere. Pair any of these with braided AN hose and hose ends for a matched setup.

How Do You Size a Fuel Line Insulation Sleeve for AN Hose?

Size a fuel line insulation sleeve by matching its inside diameter to your hose's outside diameter, then confirm the AN size it's listed for. Each AN dash number equals 1/16 in. of tube outside diameter, so -8 AN equals 1/2 in. A braided hose's actual OD runs larger than its dash size suggests.

For example, the Redhorse Performance 244 Series -08 sleeve fits -8 AN hose and has a 0.784 in. diameter. Measure your hose OD with calipers and compare it to the sleeve's listed ID before you order. A loose sleeve can slide and leave gaps at the ends, and a tight one is hard to work over the hose.

Our AN fitting and hose sizes guide explains dash sizes in detail. The AN hose assembly guide walks you through building the line itself.

What Do Heat Sleeve Temperature Ratings Mean?

A continuous rating is the heat a sleeve handles all the time. An intermittent rating covers short exposures like heat soak or a brief flame. Compare the continuous rating with the steady heat near your line, and treat the intermittent number as a safety margin for short heat spikes.

The Redhorse 244 Series pairs a woven high-temperature fiberglass lining with a 100% silicone jacket. It lists a maximum ambient temperature of 3,000 degrees F. This slip-on heat sleeve comes in a 72 in. length, in red or black, and protects fuel, oil, brake or electrical lines.

Ratings vary by brand, material and construction, so check each product's listing for its rating before you buy a sleeve for your build. DEI and Thermo Tec also offer heat protection for lines that run near headers and turbos.

How Should You Route and Organize Protected Lines?

Route protected lines as far from heat sources as you can, and keep them clear of moving parts. Secure each run so it can't rub or sag. Distance works as free insulation, so plan the route before you sleeve anything.

Use hose clamps to lock sleeve ends and connections in place. Add billet hose line separators to keep parallel fuel, oil and brake runs evenly spaced and easy to inspect under each hose protection sleeve. Where a line passes near headers or a turbo, install exhaust heat shields between the exhaust and the line as a second layer of protection.

Check your routing with engine movement in mind, since torque can shift a line toward a hot spot. When your plan is set, shop this category for the sleeves and covers that fit your build.