I just flushed my radiator at a local shop with toyota coolant and they used regular water from a hose i think to mix it with... i was told that we should use distilled water... Does it really make a difference?

 

Tap water contains many minerals, and it can lead to corrosion and scale build up in the radiator and engine cooling passages. I wouldn't panic about it, but maybe schedule your next flush sooner than you would normally, and use distilled when you do.

If you're going to lose sleep over it, change it out, it 's only about ~$20 or so with the Toyota coolant (if doing DIY) and it's not difficult.

Cheers.

 

I used to own a Mercedes-Benz, and MB said their research showed that use of distilled water caused minerals to leach out from the metal in the cooling system; so they recommended against the use of distilled water.

I suppose if you had really hard (i.e., mineral-laden) water, it might be a different story.

 

In the greater scheme of things there is only about 3/4 of a gallon of water, if that, that would be mixed with the coolant so you would never know the difference. The key is that they used the genuine Toyota coolant which is specifically designed for the water pump seals. Other coolants can cause failure.

The new LS 430 will come with a 100,000 mile coolant!

 

a lot of coolant brands allow to mix with normal tap water. Very often established coolant vendors have added additives against the corrossion.

 

I think distilled water was more important to use in the refill of batteries..not radiator coolant.