just popped into halfords to price antifreeze and they have two types, standard and "advanced". apparently the advanced is silica free for better heat transfer and anti corrosion. as this is 150% price of standard, anybody know if it does make a difference, or is just a way of getting more money out of us poor motorists?
regards.

- (#6073) eddie arrowsmith, 9 Nov 02

Eddie,
On another motoring website, this question came up and was answered by some experts. Aparently, this new spec antifreeze/inhibitor gives much longer life before degrading and gives much better anti corrosion protection for internal alluminium components, ie, cylnder heads, pumps etc. I understand that a number of motor manufacturers are specifying these fluids on their initial fill. The acronym "OAT" covers the spec (I don't know what it stands for), but, the experts seem to think that it is far superior to "ordinary" antifreeze/inhibitors.

- (#6108) John Davis, 11 Nov 02

This 'new' coolant is in fact a biodegradable compound that they manufacturers have been forced to adopt, as the european directives have stated that in excess of 93% of any new vehicle must now be recyclable, and the rest must be biodegradable, it is a vegetable based product and the experts do say that it's specific heat capacity is greater than the of ethylene gycol antifreezes (the normal blue stuff we all know & love). This being said, the blue stuff is perfectly acceptable with older cooling systems & was designed for aluminium components. I havew recently replaced all of the coolant in our townie, having both chemically flushed & back flushed the system to try o reove as much silt as possible, I put a 50-50 mix of ethylene glycol coolant & distilled water into the system, I would say that the most important thing here is to use the distilled water as opposed to tap water, it doesn't have the impurities in it that cause the scale & subsequent silt build up, this will help to keep the coolant cleaner & the system free of silt. Since doing this the gauge (admittedly the rather limited Toyota item) has been one 'blib' lower than before, even at 150Kmh.

- (#6109) Rob Drinkwater, 12 Nov 02