Modern Vespa

Before setting out for a ride yesterday, one of the more experience riders asked me when last I checked the water level on the GTS...

I had to admit that I had NEVER checked the water since I bought it in October last year!

So we searched about in the OEM toolkit and found that Piaggio had not provided the tool to open the cover. Fortunately, I had a nice set of multi-tips in the glove box and we opened it up. It must have taken a half litre of water to top up.

After our ride, I must draw some out again to put back some antifreeze solution,
which I believe must be pre-mixed.

So... when last did you check your GTS/GTV water level...?

Last weekend when I replaced the coolant !

You must have a leak somewhere ? Common place seems to be the joint under left foot board , Any drips under scooter ?

Fud, this is a very good question you pose! Well done for posting about it. It's one of those out of sight, out of mind issues. I'll second the comment super-fly made too. He and I have both had that underfloor issue. It quite common and an easy fix but annoying. If you have it you will notice the odd drip of water/coolant on the left underside of the bike where the 'shark gills' are. It normally requires a new hose clip to be fitted. You can do that without a drain down so it's straight forward enough to convert to a hose clip type that uses a screw tightening method. This is much better than the one time use clips fitted at the factory as these seem incapable of lasting for very long before they allow the hose to weep. Of course your leak could be somewhere else so do have a general check around the bike to see what's going on.

Fud, you probably know this stuff, but don't forget to use the same stuff for top up as is already in your bike. This is always worth repeating for any folks that may read this and not be sure. It should be Ethylene Glycol OAT based engine coolant, that's what they come from the factory with as far as I know in most countries now. You could check with your dealer to be sure or look in the owners manual. Other coolants often say they mix with anything but often they don't fully mix and can cause some issues later down the line, although it is ok to mix genuine OAT ethylene glycol coolants. Additionally, if someone has used something else in youir bike after doing a complete flush, and you don't know what they've used, it may be prudent to do a flush and refill. But as super-fly says, you definitely have a leak.

I used 2 clips plus cut piece of pipe out so it slid farther on joint , Better to use a single wide band clip , I did think it was leaking again but has stopped now so might have been old coolant in there or it's sealed itself

Time to flush your cooling system now that you added tap water. You want distilled water so it doesn't leave deposits behind.

I checked mine day-before-yesterday when I did a 3,000-mile oil/filter change. Also checked hub oil. We're hitting a stretch of 105-110F days, so I wanted to ensure the coolant was good to go.

I checked mine last month and had to top it off quite a bit, along with the oil. Once I get the correct coolant I'll do a flush-out on both the scoots. We've owned them for a little over two months and I'm fairly certain that it's never been done.

What is the shelf life of pre-mixed glycol antifreeze solution?
Can one carry some along in the cubbyhole without it going "off"?

I carry 2x 100ml bottles of engine oil to top-up en route.
I read that MIN to MAX on the dipstick needs 200ml of oil,
so I can top up from halfway without hassle.

Sealed container shelf life is indefinite.

What he says /\ /\ indefinite if sealed from new and almost indefinite if opened but tightly sealed. Regarding oil, does your bike use oil?

Never buy coolant level is checked when normal drive us done.