How often can I use HEET?
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 twenty degrees. However, if temperatures are closer to thirty, you may only need to use it once every two or three fill-ups.
Which is better HEET or ISO-Heet?
ISO-HEET has five times the drying power of regular gas-line antifreeze and is usually priced slightly higher than HEET. Under extreme cold weather conditions, you might want to give ISO-HEET a try. Treatment levels of ISO-HEET: One bottle of ISO-HEET will treat up to 20 gallons of gasoline.