What water to use with coolant?
 

Would like to flush out my coolant system as the coolant is already a light brown colour and it was changed this time last year.

What water should I mix with the Volvo coolant, deionised or distilled?

Also, should I do a chemical flush or just flush it with water?

PS I don't think the coolant system has ever been flushed and the car is a 2002 with 145,000 miles.

Distilled water is your first choice, followed by deionised if you can't get distilled. I would avoid using flushing agents unless there is a known issue with the cooling system. Refresh the coolant a couple of times making sure it circulates adequately between changes.

There's lots of chalk in our water locally, so there may be a case for using something else, but I don't see a lot wrong with domestic mains water in many other parts of the country.

^^^^ If your water supply is soft, fine. Hard water....not so good.

Boil it, perhaps?

have you got a non gen water pump fitted? seen these end up with rusty impellers within 3 months and turn coolant brown

I live in a hard water area so cannot use tap water.

As far as I know, it's on the OEM water pump.

Drain then flush forwards and backwards with tap water, flush with distilled or deionised water then fill with 50% of capacity with neat coolant then top up with distilled/deionised.

The full process is on my YouTube channel and my coolant is still as clean and green as it was 5 years ago when the video was made.

Thanks for the info, just found your video, really good as ever!:teeth_smile:

5 litres of water from local motor factors usually about £2.50 so pick up a tenners worth