Water or Antifreeze?

| October/November 2003


The following comes from a recent topic on SmokStak, which can be found on the Internet at: smokstak.cgi. As ever, various individuals started, commented on and concluded the following bulletin board thread.

I've been to several engine shows so far this summer and noticed some guys use antifreeze in their cooling hoppers. I was curious if anybody had any thoughts about the advantage or disadvantage of using water versus antifreeze in hopper-cooled engines. Also, if water is being used, should the hopper be drained after each run? I don't know if this affects the proper cool down period of the piston and cylinder, but I always drain my engines immediately after they have been used. - Mike

You should always use a 50/50 mix with water and antifreeze as it provides better cooling than just water alone, but most importantly it acts as a rust inhibitor. I leave the mix in all the time for this reason. You should not drain the liquid until the engine has cooled down. - Steve

You need some water, and be sure to add more from time to time, otherwise the heat will build up. The main way that water cools hopper-type engines is by evaporation. If you don't have any water then you've lost a lot of your cooling. Antifreeze will eventually evaporate some but at a much higher temperature than water. - Leonard

What about using a wood block in the hopper? It is usually to keep the splashing to a minimum. Maybe something other? I use plain water and add a small amount of 'cooling system conditioner and water pump lubricant.' It's cheaper than antifreeze and it prevents rust. I think it is a form of water-soluble oil.- Gary

Just a technical note, antifreeze added to water decreases the ability of the coolant to dissipate heat. A 50/50 mixture, although not as efficient at removing heat, does have corrosion inhibitors, lowers the freezing point and increases the boiling point of the coolant. Modern antifreezes are primarily designed for closed, pressurized cooling systems. - Richard