Hi Tominator,
Methanol is a solvent. Depending on what other chemicals are added to your coolant, such as corrosion inhibitors, dyes, etc, and also the type of rubber the components are made of, adding methanol to the mix may degrade your seals and o-rings etc. You also need to check if your hoses are chemically compatible with methanol. Methanol is also toxic to humans, even when absorbed through the skin. It is highly flammable. It also has a much higher rate of evaporation than water and you may find that your loop needs topping up more frequently. Methanol can also be corrosive to some metals and you would need to add the appropriate corrosion inhibitors. You can buy off-the-shelf automotive anti-freeze based on methanol but these are used in systems designed with materials able to resist its chemical effects. I think using methanol has significant drawbacks and hazards that will probably contribute to considerably increased expense, maintenance and monitoring of your cooling loop. I would advise against it as it just seems like a complicated alternative for minimal gain compared to what is already tried and tested.