OAT coolant
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Discussion

Jack_and_MLE

Original Poster:

626 posts

269 months

Tuesday 28th April 2020
quotequote all
Hello All.

I've recently bought some OAT coolant from Halfords, the version which need to be diluted
This one: https://www.halfords.com/motoring/engine-oils-and-...

On the Waring label it say to have a maximu of 60% coolant.

Would some one know why?

Jack

Chris32345

2,141 posts

92 months

Tuesday 28th April 2020
quotequote all
Because coolant is supposed to be a 50/50 mix of coolant and water for maximum performance/protection

Jack_and_MLE

Original Poster:

626 posts

269 months

Tuesday 28th April 2020
quotequote all
What would be the consequences if the coolant was 100% OAT?


Matt_E_Mulsion

1,746 posts

95 months

Tuesday 28th April 2020
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It doesn't work properly.

E-bmw

13,539 posts

182 months

Tuesday 28th April 2020
quotequote all
Unnecessary wallet drain for no advantage.

paintman

7,860 posts

220 months

Tuesday 28th April 2020
quotequote all
Jack_and_MLE said:
What would be the consequences if the coolant was 100% OAT?
www.midlandslubricants.co.uk/agricultural/agricultural-oils-tractor/tractor-oils-lubricants/midlands-lubricants-long-life-red-anti-freeze/
Freezing Point, Undiluted -13°C
Freezing Point, 25% aqueous, (1:3 ratio is antifreeze to water) -16°C
Freezing Point, 33% aqueous, (1:2) -19°C
Freezing Point, 40% aqueous, (1:1.5) -24°C
Freezing Point, 50% aqueous, (1:1) -36°C

Think there may also be heat dissipation issues if undiluted but I stand to be corrected!

66mpg

701 posts

137 months

Tuesday 28th April 2020
quotequote all
I can confirm heat dissipation issues with neat antifreeze: I filled up a car from a drum marked (with a marker pen) 50/50 mix. At first I could not understand why the cooling fan was running so much more than usual. It turns out that the drum had been half filled with neat antifreeze but the water had not been added. Once the coolant was replaced with a 50/50 mix the fan went back to normal operation. The specific heat capacity of ethylene glycol is lower than that of water so the coolant gets hotter from the engine’s heat and the fan spends more time running to try and pass enough air through the radiator.

Turn7

25,754 posts

251 months

Tuesday 28th April 2020
quotequote all
paintman said:
www.midlandslubricants.co.uk/agricultural/agricult...
Freezing Point, Undiluted -13°C
Freezing Point, 25% aqueous, (1:3 ratio is antifreeze to water) -16°C
Freezing Point, 33% aqueous, (1:2) -19°C
Freezing Point, 40% aqueous, (1:1.5) -24°C
Freezing Point, 50% aqueous, (1:1) -36°C

Think there may also be heat dissipation issues if undiluted but I stand to be corrected!
Every days a school day...never knew that....

66mpg

701 posts

137 months

Wednesday 29th April 2020
quotequote all
Specific heat capacities:

Water: 4.2 J/gC
Ethylene glycol: 2.4 J/gC
50/50 mix: 3.1 J/gC

Ethylene glycol mixed with water lowers the freezing point and raises the boiling point of the coolant at the expense of heat capacity but it’s a worthwhile trade off.

Dogwatch

6,384 posts

252 months

Wednesday 29th April 2020
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I bought a 20yo Corsa as a tip car and noticed it was running a bit hot. I siphoned out the assortment of years of anti freeze "top-ups" which resulted in a mix of unknown strength (and very strange colour), and refilled with 50/50 ready mix. Temperature gauge now a happy bunny!