Modern Vespa

When is it recommended to replace waterpump as I don't want to leave it till it dies

I'm at about 57k on the clock and asnt been replaced ever

I don't hear any rattling or anything yet and doesn't overheat

This is a tricky one and I know where you are coming from. It's an easy job to do so if it were mine and I wanted to be confident the engine won't let me down then I'd do it, especially if I have lots of summer riding planned. Your mileage is getting quite high now. They often go at the least most convenient time and if you don't notice it you can fry your engine which is much more costly. I don't know too much about your bike regarding what the pump life is but on the GTS the water pumps have a variable life cycle. It can go anytime after 30-35k miles. But some of my customers have still got the original pump with over 50k on the clock. It depends to some extent as to the type of riding you do. Long wide open throttle rides on highways will wear the pump more quickly, as will poor maintenance of the engine coolant. Maybe get a pump or rebuild kit and have it on standby for that day when you are not doing anything. Or of course let your dealer do it.

it's the seals on the waterpump drive shaft that fail and leak. they might not ever fail. i wouldn't worry about it.

Having rebuilt my water pump on my 2007 GTS-250 last year, you should rebuild or replace the water pump when you see coolant leaking from the vent hole. BTW its a real pain to rebuild / replace one. I purchased the ceramic face seal and oil seal from Vespa and sources the two ball bearings locally. You will be taking the stator housing off the motor to gain access to the pump which is built into the stator housing. i had success but only because I work in a machine shop. I had to make a seal installation tool to keep from destroying the face seal. If I were you I would send it to

https://www.scooterwest.com/water-pump-rebuilding-labor-waterpump.html