[TheOtherLeft]

Hiya gurus,

I've had a strange thing happen to my radiator fluid over the last few days.

I flushed my radiator a few months ago and all has been sweet. It hasn't overheated or used any water. I use Castrol concentrate at about 33%. Then a few days ago when the really hot weather started down here in Sydney the fluid in the overflow bottle has a brown tinge. I emptied the bottle 2 days ago and filled it with plain water as I was out of concentrate. I then checked this morning and the brown tinge is back so it looks like maybe the rest of the coolant is brown as well. The car still doesn't run hot. I checked the radiator cap and it still has green coloured fluid all around it

I haven't been in any mud and my last trip was at Stockton. The gearbox was a little overheated as some fluid had leaked out of the dipstick hole but it was still fine (the fluid was not burnt). Not sure how it could be related to the engine coolant though.

Any ideas?

[v.w.dave]

The extra heat can and will brake loose the rust in the system

[TheOtherLeft]

So what's the solution? Drain, flush and refill again?

Is rust too detrimental or just usual wear and tear?

[Rockhopper]

Drain, flush and refill again.
I don't thnik it's really had much to do with the weather. It's been warm, but not that hot in Sydney.
Rust is usually caused by a poorly maintained cooling sytem.
Check your oil though. If the oil has gone a milky cappucino type colour, it's time to pull you head(s) off