Antifreeze shenanigans

[FishFry]

Last night I had a long discussion with some friends on antifreeze.
I was amazed how many opposite opinions I heard on something that should have a pretty straight answer.

Ethylene, propylene, organic, inorganic, silicates, long life, distilled, non-distilled, bolt in zinc anodes andwhatnot.

Some say propylene based doesn't kill your bearings, when it gets into the oil, but it kills your seals on older engines (also silicone form-a-gasket stuff).
Some say distilled/demineralized water is corrosive and eats your engine, others say tap water makes deposits and scaling, and that some instructions say to use distilled water.

Everybody says they did this or that for 150 years (pretty much every possible combination) and never had a problem at all,
than the mechanics chime in and tell stories about leaking disasters with a certain orange type of antifreeze, they had to fix all the time etc.

The information you can find online is also all over the place and it's a mess.

I'm not a chemist, all I know for sure is that you should not mix different types, since they may gel.
On my daily drivers (most of the time 10-20 year old cars) I actually never gave it much thought. Always used the recomended type and tap water and called it a day. Also never had a problem with that. Maybe that means it's not THAT critical at the end of the day - who knows?

Can someone with more knowledge please shine some light on this?

'm having a 41 Chevy with a hopped up 261 - iron block and head, but aluminum intake (water heated) and a radiator with brass parts.
It's a mixed bag of metals. Also sometimes our winters get pretty cold, so just Water Wetter doesn't do the trick.
Distilled/demineralized water or not? Organic/inorganic? Ethylene, propylene, silicates free?

thanks, Frank

[Kevin Johnson]

Some results to look through:

https://scholar.google.com/scholar?star ... antifreeze


https://www.sae.org/search/?qt=antifreeze


https://www.hondarandd.jp/point_search_ ... tegory_id=

[Alaskaracer]

I run the Prestone yellow stuff. I've never had an issue with it mixing and gelling, and has always kept the cooling system clean.....works for me....


Funny story about antifreeze. When I worked in Alaska, we had a customer that came in twice a year to get serviced. In the spring she wanted her "antifreeze" removed and "coolant" installed....then vice versa when winter was coming....we tried to tell her they were both the same and even showed her the bottle...yet she insisted they were different and if we didn't change it her engine would either overheat in the summer or freeze in the winter....so she got a $175 coolant flush twice a year......

[Dave De]

Ive had professional experience with PG, EG, and Long life EG or LL EG. Then with adder packs for coolants in diesel apps. And high mineral based water added. My history was mainly with mechanical seal life on coolant pumps. I could write a book here but I'll just make statements from past working life tests. If you have specific questions please ask.
Elastomer compatibility is equal for PG and PE. LL EG is somewhat acidic and slightly more corrosive but did not affect life test results.
All off the shelf coolants have additional adder packs in them which are dissolved solids. These materials may fall out of solution when there is an imbalance. This can happen when water with high mineral content is used or mixed in with concentrated glycol.
If you cant use distilled water to add to your concentrated glycol you should buy pre-mixed glycol. Pre-mixed glycol uses distilled water. If you use city water there is way too much chlorine. If you use well or well water tower water there is too much mineral content. Also dont mistake deionized water for distilled. Deionized is highly corrosive and should never be used in an automotive coolant system.
Whenever extra minerals are added (which usually come from bad water) coolant degradation will occur. In gross cases the coolant will actually gel. Mineral fallout attaches to sealing elastomers and mechanical seal faces leading to wear and leakage.
Do not over concentrate. All of these glycols have low temperature boiling components so if you run high temperatures even for a brief time period the coolant will be bruised by distillation and should be replaced.
Best brand preference for low mineral content is Prestone. Worst is Peak. Mineral content is needed for good operation.
Mixing glycol types. Dont mix PG with EG. You can mix EG with LL EG. I recommend that you stay with one brand to avoid silicate or phosphate over concentration. Flushing should only be done if the coolant is damaged or expired. All Prestone products will protect the materials in your engine with aluminum as the most difficult.