Ethylene vs propylene glycol

[Bruce Palmer]

John Deere sells both for my 4045 135hp marine engines. I'm going to flush and replace, any thoughts on what is normally used? I have been told conflicting thoughts. Thanks!

 

[DavidM]

Ethylene glycol is the base for most engine antifreeze but because it is toxic, propylene glycol is used to winterize potable water systems. Ethylene glycol is somewhat more effective at increasing the boiling point of the coolant mix.

David

 

[Jeff F]

If you're running coolant through a heat exchanger for hot water propylene glycol is a safer choice.

Sent from my moto g play (2021) using Trawler Forum mobile app

 

[Cigatoo]

What Is Ethylene Glycol Coolant? Ethylene glycol is an alcohol-based organic compound that often serves as an antifreeze agent in vehicle and heating, ventilation, and air conditioning (HVAC) systems.

Good synopsis of coolants explained here. Use what John Deere recommends.

https://www.aaa.com/autorepair/articles/engine-coolant-101-the-right-coolant-for-your-vehicle

I have seen many engine coolant systems and manifolds mucked up with use of the wrong type of coolant.

 

[H2O_Doc]

Ethylene has better heat transfer properties than propylene glycol, but toxic if a pet were to drink it. Most automotive engines us Ethylene glycol for that reason.

 

[DCDC]

May be helpful:

 

[Slowmo]

Essentially all engine coolants are based on ethylene glycol. The differences between manufacturer recommendations exists in the additive systems used. About 20 years ago or so the organic acid technology (OAT) was developed which allowed much longer life coolants. This is when the dye was changed from the traditional green dye to pink or orange. Do not conventional and 'long life' type coolants because of incompatibility between the additive technologies which can result in gel formation.

Ethylene glycol is a superior coolant the propylene glycol due to higher heat capacity. The main benefit of propylene glycol is that it isn't toxic while ethylene glycol is. However substitution of propylene for ethylene glycol will reduce cooling efficiency, it is unavoidable due to chemistry.