Radiator Blues...

I have never seen or heard of this condition by using proper ethylene glycol coolant and keeping it changed. Trouble is, like fuel, there is some shocking so called ready mixed coolant in the market place. The two current affairs programs on the 7 and 9 have covered this subject and showed how poor some of the un-known brands were, and think Choice magazine may have as well. I only buy the Mobil concentrate or one of the major brands, and saw Valvoline in concentrate the other day correctly labelled with what was in it, and then mix it myself with de-ionised water from the super market.

If he had not changed the ethylene glycol coolant in two years, he was well passed the use by date of the coolant. Ethylene glycol is only good for a maximum 18 months, and should be replaced every 12 to 15 months. I think you will find what all this white stuff was, was that the radiator core was aluminium, and the head and/or block as well. With ethylene glycol after the 15 month period, it starts to get acidic like viniger, and causes corrosion. The white deposits would have been aluminium corossion, which is technically just like rust. However, I would still suspect the original coolant brand he used, because at two years the amount damage/corrosion you advise is way above what is normal, even if the coolant had not been changed.

It is highly advised to change *ALL* the vehicle fluids every twelve months, including brake fluid, power steering fluid, all transmission oils and coolant etc.

Here's a couple of senerios that may shine some light,
1/ Most blocks have a drain & sometimes is overlooked when replacing the coolant which can release about 2 litres of coolant, if not drained properly the coolant breaks down turns acidic then contaminates the new coolant, therefore will breakdown quicker then over several changes the acidity is stronger and contaminating the metal surfaces therefore the effects on the softer metal becomes accelerated therefore the radiator gets blocked in a seemingly short space of time.
The radiator still works relitively well at 40% blocked.
2/ A stray current can be common diagnosis from some radiator service centres because the results look very similar. as water is conductive electricity can travel through it and pitting softer metals especially alloy.
This is usually low voltage of which is easy to check if condition exists, by using an anologue multimeter earth to earth & positive to touch the coolant/water in radiator with the vehicle running, the needle should move much well not to redgester.But not to be done immediatly after or for a couple of days of coolant changed because there will be a reading
due to the coolant structure has a positive charge and takes this time to neutralise.
I've had the second one recently caused by a fracture in a 130w globe base, it destroyed the radiator in 2 months.my high beams are used daily. hopes this helps??

For those who are interested in radiators and their associated problems, a site to look up is http://www.are.com.au/index.htm
Check out their tech section and particularly the "horror photos". It really makes you think much more carefully about the mixing of different coolants and stray current problems.
Regards Andrew.