What Is HEET Fuel Additive?

Discover the benefits of HEET with Blain’s Farm & Fleet.

HEET is a line of winter automotive chemicals. Much like the word “Kleenex” is sometimes used to describe any brand of tissues, “HEET” is sometimes used to refer to any fuel additive that removes water from your fuel system.

These chemicals are called “fuel line dryers.” Water in your fuel can cause a lot of different problems, but the most common (and frustrating) is frozen fuel lines.

How does HEET work?

When the weather outside is below freezing and you have water in your fuel system, the water can freeze and block your fuel lines. This will keep your car or truck from starting. Fuel line dryers break up the water in your fuel into small droplets that combust in your engine.

Another problem caused by water in you fuel tank is “vapor lock.” This happens in warmer months because of water condensation on the inside of your fuel tank. Vapor lock can cause your car or truck to start hard and run rough.

You can stop this problem by adding HEET to your fuel every one or two fill-ups and by keeping your fuel tank as full as possible.

What is Iso-HEET?

Iso-HEET is a form of HEET that removes water and cleans fuel injectors. This is sometimes referred to as “isopropyl” because of its main ingredient.

Iso-HEET can help increase your fuel economy by keeping your engine running more efficiently.

How often should I use HEET to keep my fuel lines from freezing?

Many mechanics recommend that you pour a bottle of HEET into your fuel tank every time you fill up during the winter months.

This is the best practice when it is consistently below 20° F. However, if temperatures are closer to 30° F, you may only need to use it once every two or three fill-ups.

Is HEET safe to use with my other fuel treatments?

Yes, but most complete fuel treatments and fuel stabilizers, such as Sea Foam, Sta-Bil, and Star Tron Enzyme, already remove water. If you use those, you shouldn’t need to use HEET to keep your fuel lines from freezing in the winter.

You can add HEET for extra strength if you are using these other products but are still having water or vapor problems in your fuel tank or lines.

For more vehicle guides and how-tos, check out our Maintenance & Repair Blog.