Hi everyone! I have a Ford Focus MK3, 2.0 Duratec engine, 49k miles, for which I wanted to change the whole coolant/water mix for maintenance purposes.

The manual says the whole capacity is 6.5L, 50% should be concentrated coolant and 50% distilled water.

So I bought 4L of Total coolant (organic, red color); 3L to use for sure and 1L just in case it needs a bit more, aiming to save what’s left.

I brought the 4L to a mechanic who did the whole job. Sadly I wasn’t clear enough and just trusted that he would know but… he actually put all of the 4L of coolant and completed it with distilled water.

So now I guess the car has a mix with approximately 65/35 coolant/water which is not what the manual suggests, but the mechanic told me it is “better” that way.

What do you suggest?

  • Do I move on and just keep an eye on the temperature indicator? (I read that coolant’s heat transfer capacity is not as good as water’s).
  • Do I, somehow, “adjust” the mix by getting some out of the deposit and filling with water? I don’t know how to “get some out”, but I read some people use turkey basters for removing excess.
  • Do I replace everything again? The bad part is all of the cash I spent on the 4L of coolant and the mechanic’s work.

Thank you in advance!

  • HeavyDropFTWBEnglish
    1·
    1 year ago

    You seem to be asking questions while already having your mind made up. Were those rhetorical?

    Pure water dissipates heat better than coolants. So it would be logical to say that pure water could keep an engine cooler. Pure coolant would keep an engine a bit hotter. Keeping with this logic, having a 60/40 mix of coolant/water would keep an engine just a bit warmer than a 50/50 mix.

    The main two issues with running pure water are freezing point (as you mentioned), and the corrosion protection additives in coolant. If we didn’t have to worry about either of those issues, people would be better off running pure water all the time.

    In OPs case, they likely have enough anti-freeze properties in their coolant. It likely won’t over heat. And they likely have enough concentration of anti-corrosion additives as well.