Antifreeze temperature

theone8181 · 4 Dec 2016 at 14:58

Hi guys I've got a gauge for checking the freezing temperature of coolant in the car. Currently it's reading -5 or so but I just wondered if it drops to say -10 how long would it take to freeze or would it not be an issue.

Diagro · 4 Dec 2016 at 15:03

Normally -20 is what they are made to go to

chaparral · 4 Dec 2016 at 15:12

Also make sure to only check it when the water/engine is cold

I find if you check it while the water is warm or hot the tester will give a totally different reading..
But this may not effect all Antifreeze testers as some have a thermometer for temperature calibration.

m4rmite · 4 Dec 2016 at 15:23

Concentrate antifreeze should be specced to give protection to around -37C using the manufacturers dilution rate.
The pre-diluted stuff will not get to those temps but should hit around -20C.

Do you have the option of topping up the system with some more antifreeze to give it some more protection?

theone8181 · 4 Dec 2016 at 16:32

I can do, the engine was still quite warm however the tester I'm using is a glass vial with a float in the middle so not sure how good it is. I think I might just bang a big more antifreeze in there.

m4rmite · 4 Dec 2016 at 16:45

The glass vial with the float in is extremely accurate as its an hydrometer, however temperature affects the SG of liquids - you can adjust with a temperature compensation chart but that's getting a bit anal.
Hydrometers are made to show the dilutions of the Specific Gravitys of water and ethylene glycol (antifreeze) to give you a mixed ratio.

Top it up and jobs a good one.

if you can test with the coolant/water at 15c even better as that is what the hydrometer will be most accurate at.