Do I add more anti-freeze when topping up with water?

Post by **moggiefan** » Sat Dec 12, 2009 4:34 pm

Our beloved Snowberry four-door, Mrs Wilberforce, has had a Winter semi-service, during which anti-freeze was added, seeing as she's (sadly) sat out on the road. When topping the radiator up with water, do we need to add any more anti-freeze? If so, what's a good rule of thumb (1 part to 10 parts water, etc)...

Any help most gratefully received!<br>

<br>

Post by **PSL184** » Sat Dec 12, 2009 4:43 pm

I usually maintain a 50/50 mix however, check what you buy. Most places already sell premixed antifreeze - for some reason it is difficult to buy neat antifreeze these days? How often are you topping up? Its not something that should need doing regulary unless you are using water or have a leak?

Post by **PAULJ** » Sat Dec 12, 2009 5:33 pm

50/50 will protect down to -36 so when you change antifreez as PSL184 says use 50/50 mix then if you do have to top up and all you have is water it wont matter. A hydrometer will tell you how strong your mix is

Post by **bmcecosse** » Sat Dec 12, 2009 8:08 pm

As above - why are you topping up ? You shouldn't need to!

Post by **moggiefan** » Sat Dec 12, 2009 8:11 pm

Thanks guys, still a bit confused, though.

The semi-service was back at the beginning of October and the 'force is a daily driver, so we thought we'd better check the level in her radiator. We put in just under half a litre of water today as it was a little low. As far as we're aware, keeping an eye out for water/oil spots underneath, we have no leaks.

So we should just buy a 'premixed' 50/50 antifreeze and use that to top up the radiator in two-three months, is that right? Then when we have our next service, the garage will drain the radiator and put just water back in, until our next Winter visit, when they'll drain that and put a 50/50 antifreeze mix in...

Post by **rayofleamington** » Sat Dec 12, 2009 8:16 pm

You can get neat antifreeze - but you'll less likely to find it at supermarkets / halfords / pound shops compared to the diluted stuff.

If you are the type to carry radiator water (for emergencies), plain water is not always a good thing to have in winter - you can't use it when it's frozen solid, after being sat in the boot!
I tend to carry pre-mixed water / antifreeze (usually I mix up 33% as 50/50 uses up more antifreeze...).
Topping up with water is ok, if it's only a splash once in a blue moon, but any more than that, and you quickly dilute the antifreeze levels. Freezing up in winter can damage the radiator / water pump / head and block, so it's best avoided. However you should prefferably avoid using straight water at any time of year, as antifreeze contains corrosion inhibitors which protect the engine / pump / radiator all year round.

Post by **bmcecosse** » Sat Dec 12, 2009 8:40 pm

Yes - just leave the anti-freeze in - don't drain it.

Post by **moggiefan** » Sat Dec 12, 2009 10:40 pm

Thanks, that's what we'll do, then. Seeing as we just did a near-three-month radiator top-up with water, we'll add a bit of antifreeze, then carry a mixed bottle of radiator water/antifreeze in the car for emergencies, and top up with this 50/50 mix in future. Much appreciated!

Post by **dalebrignall** » Sat Dec 12, 2009 11:12 pm

just use a 50/50 mix you cant go wrong then ive done that for years .

Post by **katy** » Sun Dec 13, 2009 11:45 pm

Don't fill the rad right to the top when it's cold. Ideally, when it's cold, the liquid level should be about 1/2 way between the top of the core and the filler hole. It needs room to expand when it heats up.