Well, since I have seen 'prestone' and others selling the 50/50 premix in the stores and I have lately seen blown radiators, literally burned up fan belts and chewed up water pumps, blown heater cores, and broke engines.....
I do live in Canada where we have cold days.....
So here is how a radiator flush works. You run water through everything with the rad drain and 'hopefully' the engine block drain (although 99% of the places that flush don't open the engine drain!) and the heater hoses off so you can flush out the heater core, then you put it all back closed and want to fill it.......
Before I go on, I will bet a beer if I could see you that when you open the 10 year old engine block drain it will need to be reamed with a coat hanger to get the liquid to flow out clear running with the hose input..... There will be a bunch of metal/rust flakes plugging things up...
OK, so you now have flushed it out.
You then need to know how many quarts or liters the coolant system holds.
My system holds 12 US quarts.
So if I go by the coolant makers charts, as an average, a 50/50 mix is good for -35F to -38F or so, right.
I just flushed my Jeep's system and want -58F or at least -40C/F so according to the charts I need 7 out of 12 quarts to do that.
When I add 7 quarts of pure coolant, the add water, I only can add 2 or
3 more quarts of water!
That means 30 or 40% of the system is already full of water. The heater core and block.
If I used the 50/50 mix, with 'say' 50% of the water still in there, just for easy numbers, the percentage of coolant will be seriously low allowing the vehicle to freeze and destroy the rads and engine......
Be 'REALLY' careful with the 'convenient' junk folks!
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Aug./05