VW Golf coolant topped up with water – safe to use car?

BillieBob

Hey all,
Last weekend the coolant red warning light came on (with STOP!) and after consulting the manual I topped up the low coolant with water (c. 350ml tap water, not distilled water). My car is a 07 VW Golf and handbook said only G12 coolant is to be used (in a mix of 40% to water). The car is booked in for a service next week (and will note to garage then that the coolant was topped up with water).

However my OH is due to use the car this weekend for a trip away. With the low temperatures forecast for the weekend is it safe for her to still use it? Would the tap water increase the risk of the coolant freezing on a v. cold night? If I topped up the reservoir with c. 140ml G12 coolant would that protect it from any frosty cold nights and get it through to next week ok?
All feedback welcome.

Bpmull

It's fairly impossible to tell without knowing the concentration of water and coolant currently in it. But assuming the mix was correct concentration before and you added 350 ml of tap water and then 140 ml of coolant then that should be ok provided there isn't mad low temperatures. But If someone was already adding water to it the concentration of coolant/ antifreeze could be very low.

But tbh your missing the whole problem here modern cars don't use coolant its a closed system so level should remain the same unless you have a leak. So if you go driving around in it and the leak is severe then you will be losing a lot of coolant. So realistically you need to bring it to the garage get them to find the leak fix and get the coolant antifreeze replaced so that you know all the concentration are right and it's supposed to be changed every 2 years anyway.

mgbgt1978

With regard to the low Temperatures over the coming days. The forecast is for Lowest Temps of around -2c or so at night. Hardly excessively cold.
If your car had the Factory recommended coolant set-up it would be OK down to -25c at least. I'd say you're fairly safe even if it only has 1/2 the coolant ratio that VW recommend.

George Dalton

It should be fine once the coolant in the car was previously at the correct concentration.

Jesus.

Throw a small drop of coolant into it anyway. She'll be grand.

greasepalm

what you need is one of these