Coolant overdiluted
Coolant overdiluted
Author
Discussion

Petrolsmasher

Original Poster:

2,452 posts

147 months

Tuesday 15th October 2019
quotequote all
Needed to top up my coolant so added deionised water to some coolant i had in my boot, however after diluting it and filling the header tank i realised it was diluted from the last time i used it.

How much of a concern is this, i topped it from min to max in the header tank.

Also ive topped it up twice over the last 2 years and may have done this once before also, just from min to max, the last time it was diluted was with tap water also, how much of a concern is this?

Miserablegit

4,449 posts

140 months

Tuesday 15th October 2019
quotequote all
It’s probably due replacing soon anyway so that would be the best option.
However if you just empty the header tank and fill it with neat antifreeze of the same type you’ll be ok. Any scale from the tap water will have formed by now anyway.
The specific heat capacity of coolant is lower so you might need to dilute in the summer ( or change the lot by then) but having a slightly under-diluted coolant mix shouldn’t cause you problems in the winter

Weekendrebuild

1,120 posts

94 months

Tuesday 15th October 2019
quotequote all
No real concern unless we have a severe winter an it freezes your probably ok for now . You can get a little coolant checker it takes a sample from header an will tell you how diluted it is .

By the sounds of it a coolant flush wouldn’t go amiss, it can be topped up properly then . Doing 2 vans at the weekend leaky bottom hoses so excuse for some extra maintenance, winter prep

ging84

9,548 posts

177 months

Tuesday 15th October 2019
quotequote all
this is no concern

Most coolant is designed to be mixed with tap water, there will be a maximum recommended hardness, but water in UK will rarely be hard enough to be a concern. Normally its places where they use desalinated seawater where tap water is unsuitable.

Topping up with plain water is normally fine, you usually aim for a 50/50 mix, but going down to 40/60 will make almost no difference.

Slow

6,973 posts

168 months

Tuesday 15th October 2019
quotequote all
My cars all run just water unless it didnt leak and came with something else in it.

I live in the north of Scotland and not once had any issues with freezing. I wouldnt worry.

carl_w

10,781 posts

289 months

Tuesday 15th October 2019
quotequote all
Slow said:
My cars all run just water unless it didnt leak and came with something else in it.

I live in the north of Scotland and not once had any issues with freezing. I wouldnt worry.
Do you use them regularly? I managed to pop out all the freeze plugs in the engine of a track car the winter before last, and in South East England.

227bhp

10,203 posts

159 months

Tuesday 15th October 2019
quotequote all
Some lovely internally corroded engines running around there then.

Miserablegit

4,449 posts

140 months

Tuesday 15th October 2019
quotequote all
Slow said:
My cars all run just water unless it didnt leak and came with something else in it.

I live in the north of Scotland and not once had any issues with freezing. I wouldnt worry.
Let’s hope there are no iron block and alloy head combinations in your fleet that have leaked and are now running water only


GreenV8S

31,027 posts

315 months

Tuesday 15th October 2019
quotequote all
Slow said:
My cars all run just water ... I wouldnt worry.
You should be worrying about corrosion, then.

Slow

6,973 posts

168 months

Tuesday 15th October 2019
quotequote all
GreenV8S said:
Slow said:
My cars all run just water ... I wouldnt worry.
You should be worrying about corrosion, then.
Never had any issues, owned several cars for 5+ years and over 50k miles without any problems.