Does coolant help with heat transfer or does it only help with boil over, freezing, and corrosion?? We used to run straight water in our sprayers back home 'cus the shop guys said they run hotter whit antifreeze...

 

Sarge,

Those guys "back home" were correct, for the most part. Water alone is a better agent for the transfer of heat. It has a latent heat capacity better than most other liquids. There are some specialty solutions that have a higher latent heat capacity, like nuclear reactor coolants, but those are tough to acquire in most places and don't afford a lot of freeze protection.

The problem with pure water is the lack of corrosion and freeze/boil protection. For that reason, you need to add something to protect the metallic surfaces from corrosion and keep the solution from freezing and boiling. Wood alcohol used to be used commonly to prevent freezing, and it didn't detract from the latent heat capacity of the water. Unfortunately, it doesn't offer an lot of boil or corrosion protection, and would evaporate out of the system regularly.

Common polyethylene glycol additives are a good solution, but will detract from the latent heat properties of water. For that reason, you should mix the solution as lean as possible. Modified polyethylene glycols (without silicates) are a little better at heat transfer, and afford better corrosion protection. Those are some reasons I've switched almost all my vehicles to Dex Cool. The negative side is the cost of the concentrate, and the fact that because it has a smaller molecular chain (allowing better latent heat characteristics) it can seep or wick out of the smallest openings. Your system really needs to be tight to be able to use it without leaks. Again, use only as much concentrate as necessary to provide freeze protection.

There are other short-chain molecule additives that can enhance the latent heat properties of antifreeze solutions, such as water-wetters. Used in conjunction with regular antifreeze mixes, you can have acceptable heat transfer as well as corrosion, boil, and freeze protection.

 

Hmmm, my next door neighbor is a submariner. Wonder if he has access to some nuke coolant? Then again, I'd better not ask . Thanks for another class Vader. Be advised I'm getting a pretty good book together from your knowledge and wisdom. I'll be flushing my cooling system next weekend so I'll be sure to try the water wetter's then.