Radiator coolant/water ratio?

au350hp · 31-07-2018, 08:12 PM

What % coolant to demineralised water have people had the best results with?
I have a 2001 302 Windsor which got a new radiator & hoses around a year ago. There are no temperature issues but I would like to flush the cooling system before the Sydney summer.

GASWAGON · 31-07-2018, 08:35 PM

Old rule is 1/3 Coolant to 2/3rds water.......OR 33% Coolant. (Concentrate not pre mixed!)

happy1 · 31-07-2018, 08:43 PM

Hi,
Wouldn't this depend very much on the quality of the coolant, and if it's a 'concentrate' or not?

I would get the best possible coolant at a reasonable price (some are marked with '5 year', some are marked with 350.000km guarantee), and I would follow strictly the mixing ratio described on the bottle.

Cheers,

**GO FURTHER** · 31-07-2018, 08:59 PM

The higher the coolant antifreeze ratio... The less cooling efficiency you get.

The specific heat of antifreeze is less than that of water.
This means that for a given temperature change, the antifreeze will carry less heat each time it circulates from engine to radiator and back.

So a 50% / 50% ratio of coolant concentrate to water provides good corrosion protection but less cooling effectiveness.

A 33% ratio of coolant concentrate to 67% water, will give better cooling efficiency in Australian climate conditions and good corrosion protection.

**GasoLane** · 31-07-2018, 09:34 PM

One of the few Penrite coolants recommended for my (non Ford) car is the Penrite 7 Year 450,000KM Green Concentrate.

But says it should be used at a concentration level of 50%

au350hp · 31-07-2018, 11:58 PM

Thanks for all the advice. I have used Penrite for everything else so may as well continue the trend with the Penrite green. Interesting comment on the 50% mix though and as GasOlane says, that's what Penrite recommend. Is their mixture somehow more effective at that ratio? I remember when I changed he radiator & hoses that X amount of water stays in their so do a flush after a few kays.

MattSAU2XR8 · 01-08-2018, 12:54 PM

I'd go by what it says on the packet, and also:

- Choose the longest lasting coolant available - I think for example Nulon make a ten year or 1 million km coolant now?

- Make sure the manufacturer says its suitable for your car

- Flush the radiator properly with tap and then distilled water

- Mix it with distilled water in the highest ratio of coolant to water recommended on the pack - unless you have overheating problems more corrosion protection would be better than less

- Change it out at about 2/3 of the interval recommended by the coolant manufacturer. Given a coolant change is only going to cost about $100 and a few hours of your time, if it saves you a single radiator, heater core, transmission heat exchanger, or welch plug its paid for itself many times over :-)

GASWAGON · 31-07-2018, 08:54 PM

Nulon now make a very LOOOOONG lasting Coolant called.......... ONE.

Its in all Auto shops.

The idea is that it only ever gets filled/fitted ..........ONCE and supposed to last FOREVER!!!!!

I run Nulon Semi Synth 15W40 in my BFWGN too!!!

Will fit Nulon ONE next year i think???

123Cat · 01-08-2018, 01:00 PM

And check for residual current of course ,

I have 0.15 volts in the ED I6 radiator water with the engine on and

with 2 small bottles of Natrad conditioner with tap water, changed every year

Modern cars look like they have no residual current , It must be the very good non conductive coolants these days ,??????