Does Rear Heater Need to be On?

[FCD]

Then my only idea would be to after having flushed the system with distilled water, add some, maybe 1 or 2L of pure concentrate before adding your 50/50 mix? or mix your coolant 60% coolant 40% water.

 

[Snagglefoot]

You can get some useful data by looking up the total volume of the cooling system and then measuring the amount that actually comes out when you drain the radiator.