Minimum coolant for corrosion protection?

Joined
Jan 29, 2014
Messages
723
Location
USA
Hello everyone, I am wondering what the minimum percentage of coolant required for effective corrosion protection is. I live in the south and good cooling is much more important here than freeze protection since it hardly ever gets below freezing and I park my car in my garage overnight, so I really don't need any freeze protection. What would be the minimum amount of coolant that could be used while still providing effective corrosion protection? Thanks in advance!
 
Originally Posted by Char Baby
They work hank-in-hand. If you raise one, you raise the other and visa-versa.


What I mean is; a stronger concentration of coolant/antifreeze benefits both the cooling ability as well as the overheating ability. A weaker concentration lessens both as well.

That's why a 50/50 mix of coolant and distilled water is a good starting place. If you live where the outside temperatures are at the extremes then you may want to move to a 60 coolant/40 water mix. This will aid in both cooling & overheating. I have heard of people going to a 70/30 mix in e.g., Death Valley, CA or The Twin Cities, MN
 
Hi,
If freeze protection is not a concern & you want maximum cooling efficiency, water is the best. Water alone will provide zero corrosion protection.
In the summer I have run water with corrosion inhibitor added. I think the brand I used was recommended at 2% dilution so 1 litre lasts a long time.
Cheers,
Iain.
PS.
https://www.morrislubricantsonline.co.uk/ankorsol-anti-corrosion-fluid.html
 
Last edited:
In most North American climates a 50/50 mix of coolant and water will suffice. In extreme cold a 60/40 will insure
not freezing up if it goes below -34*F. In climates that never see freezing temps a 40/60 might cool a bit better
because of the additional water content. In any case I wouldn't go below 40/60 or above 70/30....IIRC the coolant
manufacturers even recommend this....
 
Generally the recommendation is absolutely not to go below 30%coolant. Because below that boiling point is significantly reduced and corrosion risk is increased.

So, shooting for 40% coolant in hot weather climates is perfectly safe.
If you really want to push it, 30-40% range is likely safe.

If we're talking high elevation or some very specific situation you may want to proceed with more caution as boiling can become a bigger concern.
 
Corrosion Protection is important. Trying to skimp on it will come to light if you ever have to pay to have a heater core replaced. Also, as stated, the boiling point is raised with concentration.

6A936CEC-9BB3-4CC0-A29E-9BA42F60B5E1.png
 
Do not use water with water wetter or another additive. Use the coolant recommended by the manufacturer for your vehicle, and at least the minimum concentration stated on the container or in the owner's manual. There is zero reason to use water with the wetter additive in this application. Do not go below the concentration the manufacturer specifies.
 
I will never touch water wetter again. Google "Brown Gunk" and find that as the product breaks down it turns into a brown greasy gunk that hangs around even after flushes. I know because i did it.

That said If heat is an issue your thermostat will have more to do with heat in the engine that the coolant you use to remove it. 20-30% coolant is good enough IMO.
 
Originally Posted by kschachn
Do not use water with water wetter or another additive. Use the coolant recommended by the manufacturer for your vehicle, and at least the minimum concentration stated on the container or in the owner's manual. There is zero reason to use water with the wetter additive in this application. Do not go below the concentration the manufacturer specifies.


+1
 
Originally Posted by Char Baby
Originally Posted by Char Baby
They work hank-in-hand. If you raise one, you raise the other and visa-versa.


What I mean is; a stronger concentration of coolant/antifreeze benefits both the cooling ability as well as the overheating ability. A weaker concentration lessens both as well.

That's why a 50/50 mix of coolant and distilled water is a good starting place. If you live where the outside temperatures are at the extremes then you may want to move to a 60 coolant/40 water mix. This will aid in both cooling & overheating. I have heard of people going to a 70/30 mix in e.g., Death Valley, CA or The Twin Cities, MN

Actually plain water is the best coolant, antifreeze decreases its heat transfer ability. From a cooling standpoint, the only benefit to using a coolant mix instead of water is a higher boiling point. However, in a modern car with a pressurized system, this isn't as critical as it used to be back in the days of unpressurized cooling systems. For example, I have a 19 PSI radiator cap, which raises the boiling point of plain water to about 258 degrees. Adding 50% coolant would increase the boiling point by about 15 degrees to around 273 degrees. However, the reality is the coolant should never get anywhere near either of those temps. And if it does get that hot and the driver doesn't take action, they are taking a serious risk of destroying the engine regardless of what the cooling system is filled with. Despite what Evans waterless coolant says, just because the coolant can handle the heat without boiling doesn't mean that the engine can.
 
Just to expand on what I said earlier...and perhaps some clarification

You will get corrosion protection to as low as 10% coolant.
But not enough for the product to be guaranteed to X miles/years, or even to provide the same corrosion protection needed for shorter intervals.
I don't think there is much information out there on this as they really don't want you to venture that far from 50/50.
And the improvement in heat transfer from small changes in concentration are not significant really.

So, again 40/60 is safe. And most concentrates will provide information on that.
I wouldn't feel that concerned about 35-40%, but would start to worry below that.
 
Febi-Bilstein indicate on their coolant bottles that 30% Coolant - 70% Water is the minimum for appropriate corrosion protection.

Here in Spain though most Auto Parts Stores sell 10% , 30% and 50% Premix.

I work at one and the 50% hardly sells, 30% a little more, 10% by far the most popular.... people seem to think that because it only drops below freezing at night for a few weeks in Jan-Feb that they can just run water or cheap horrible green Phosphate-Borate IAT coolant in a modern car...
 
Originally Posted by FordCapriDriver
Febi-Bilstein indicate on their coolant bottles that 30% Coolant - 70% Water is the minimum for appropriate corrosion protection.

Here in Spain though most Auto Parts Stores sell 10% , 30% and 50% Premix.

I work at one and the 50% hardly sells, 30% a little more, 10% by far the most popular.... people seem to think that because it only drops below freezing at night for a few weeks in Jan-Feb that they can just run water or cheap horrible green Phosphate-Borate IAT coolant in a modern car...

That is interesting, thanks for sharing! Here in America 50/50 is the only premix I have ever seen. Do the people who run 10% coolant have corrosion issues?
 
Originally Posted by FordCapriDriver
Ofcourse, i did too before i joined Bitog and didn't really know much about Oils and coolants.
Yes it does cool better, but 10% really is not enough for proper corrosion protection.

Thanks. I wonder if 10% may be enough with an additive? Amsoil's Coolant Boost seems to have some pretty impressive corrosion protection https://www.amsoil.com/p/dominator-coolant-boost-rdcb/
 
Originally Posted by SpitFire6
A proper corrosion inhibitor does not need or require glycol.
Glycol is for freeze protection.

I did not know that. I knew that antifreeze contained corrosion inhibitors, but I thought the ethylene glycol was the main corrosion inhibitor and the other corrosion inhibitors were to help the glycol protect better.
 
Back
Top