SILICONE ENHANCEMENT?

QI treated my 1973 MG Midget to a set of silicone hoses. The guarantee says that the hoses must only be used with ethylene glycol coolant and ‘organic acid technology-based coolants are specifically excluded from this warranty’. I’ve been using OAT in the Midget for 20 years without problems. Should I discard the hoses and fit standard ones? Martin Pagett, Ormskirk

Theo Says:

AEthylene glycol is the most common antifreeze and is either mixed with inorganicor variants of organicacid technology technology (IAT and OAT) corrosion inhibitor packages, arbitrarily denoted by a dye. IAT (+/-2 year life) is recommended for older systems comprising various metals and solder;

OAT (+/-5 year life) and its variants for newer engines with aluminium radiators/heaters. Some types of OAT packages can soften silicones and nylon, which is probably why your hose manufacturer has included that warning.

It is possible to buy a longlife antifreeze that’s compatible with silicone, however, and if you’ve used OAT in your engine for years with no ill effect on the metals/solder, then that may be the way to go for you.