Thread: Propylene Glycol coolants.

Hi Dave
I don't have any direct experience of using the propylene glycol but my (admittedly limited) knowledge is that the only advantage is the non-toxic nature as you've pointed out. So gets used in marine environments and in the food/brewing industries where the pollution risk is high.
From a performance perspective, the antifreeze benefits and anti-corrosion additives may be on a par with ethylene but the higher viscosity and much lower thermal conductivity of propylene would presumably make the engine run hotter?? I'm thinking small, relatively hot running engines powering a brick (300Tdi....!) might not like it!

From Penrite:

What is the difference between Mono Ethylene Glycol and Propylene Glycol?

The main difference between Propylene Glycol and Ethylene Glycol in antifreeze/antiboil coolants comes down to the toxicity levels and efficiency of performance.
Ethylene glycol has superior heat transfer properties whereas Propylene Glycol has a very low toxicity level.
These differences also dictate where they are best served. Propylene Glycol based coolants are suited to environments where their low toxicity levels will not cause harm such as in marine and outdoor areas whereas Monoethylene Glycol is more suited to modern hotter running motor vehicles where its better heat transfer properties can be utilised.