Hi all, I've this evening realised that I've used a silicate coolant (blue) to top up my 916's expansion tank rather than an ethylene glycol coolant as suggested by the Haynes manual. I used hardly any (topping up from just below the min line to the max line). It was a few months ago that I did this but have only this evening come to realise what I've done. I'm now flapping that I may have caused harm. Could anyone with the know-how please comment as to how big an issue this might be please? Thanks in advance as always.
Blue and red coolants aren't compatible and shouldn't be mixed. They can form a gel blocking the cooling system. Best to drain the system, flush it and refill with either red or blue coolant.
I don't think there is any kind of industry standard for coolant colours, have even heard particular BMW blues can't be mixed. Regardless, you are probably ok with that small amount. Drain the system and check the fluid for any signs of reaction, flush with water, then fill with water and run it for a few mins then drain again. Look into the radiator for any buildup, you could also remove the pump cover and have a look there. Refill with fresh coolant.
I did the same on my Yamaha RD250LC and replaced it with silicate coolant and then rode it and left it for months. I then realised my mistake and flushed the system and put the correct coolant in. It did no harm, but I barely ran the bike, so it was just sitting there. My big worry was whether it would attack my silicone hoses, which it didn't.
