|Originally posted by Gall757:|
Don't know how it is in Australia, but here in the States radiators can be rebuilt without much problem. The shop takes it apart and re-fluxes it back together, and then you are assured that all the tubes work again. The fluid should never look murky and brown. A lot of people think that the stuff in your coolant is just anti-freeze, but it does a lot more than that and it should be in your car to protect the various metal parts.
Doesn't antifreeze also raise the boiling temperature of the coolant? Water not under pressue boils at 212o
F and I think a 50/50 mix not under pressure is supposed to boil around 225o
F if I remember correctly. Under pressure those temps rise a bit but the mix always boils at a higher temperature.
As to the OP's post. If your having boiling problems on the highway it sounds like you are frequently filling the radiator back up. Are you following the correct fill procedure to make sure your not leaving air in the system? Have you checked your radiator caps to make sure they are the correct pressure and that the gaskets in them, the rubber rings, have not gotten hard or cracked? I have a Neon that would occasionally boil in the overflow when I drove the car for longer than "normal" trips. It never boiled over and the coolant was full when I checked, so I didn't start looking for the problem right away. When I finally started looking I found the radiator cap gasket had gotten hard and cracked around the center. This lowered the boiling temperature of the coolant as it was no longer "under 14 PSI of pressure" so when the coolant got hot enough it would boil and the steam would come through the bad gasket on the cap and out the overflow. Basically, the coolant tube "could" be the problem but there are many other things it "could" be also.