Thread: Coolant Replacing

In the Line maintenance manual d02870, there is an instruction to remove the bottom attachment screw of the water pump. Fair enough, but then there is an instruction to detach the lowest position cooler hose. Now I wonder if this implies that detaching this hose is sufficient without detaching the pump lower screw.

I prefer not to disturb stuff that is not leaking!

Has anyone done this job without loosening the aforesaid screw, and still gotten the full complement of old coolant into the bucket? (thereby proving nothing else needed to be disturbed)

And would there be any airlock issues when refilling?

Hi John,

Just take off the bottom coolant hoses on the radiator one at a time and just blow down through the refill cap on the top. It all comes out. No refill issues just top it off. Drain and refill the reservoir. If I remember right you don't have the coolant thermostat. I don't ever bother with the water pump screw since you can't get to it on our planes. Make sure you use a Dex Cool compatible coolant and silicate free. Most coolants now days are silicate free, but not all.

I talked to a friend of mine that is a Rotax overhaul tech and he thinks my idea of flushing the wood part out may work, too.