How to: change your coolant for the winter months

I own and run a Yamaha TZ250 race bike, and to comply with racing regs the cooling system must be filled with de-ionised water.

This is because antifreeze, and other coolants, have the potential to act like an oil spill and require special attention from the marshals to clean up.

But during winter when the bike is in storage, I always replace the water with coolant to prevent damage from frost – this is one of those lessons learned from bitter experience.

Several years ago I didn’t bother adding antifreeze; I just drained the water and left the system empty. But what I encountered when I recommissioned the bike made me regret that decision.

There was so much oxidisation – for example in the water pump the residual dampness had caused pockets of whiteish
corrosion which I had to spend loads of time cleaning off.

The oxygen and dampness formed the perfect ratio to propagate the white alloy fungus. This wouldn’t have happened if coolant had been added because of the corrosion inhibitors and lack of air would have protected the alloy. Lesson learned!

Anyway, here’s a step-by-step guide to changing your coolant…

1. Strip for access

We say bikes are water- or liquid-cooled but what they actually use is ‘coolant’, a mixture of corrosion inhibitors, antifreeze and lubrication agents. This fluid should be changed roughly every two years, or at a specified mileage. First, work out how to gain access to the radiator cap, draining bolts and coolant expansion tank.