Modern Vespa

Hello MV- Been all over MV for a few days now trying to solve this mystery. Yes, I have a coolant* leak, and it's coming from... Whatever this thing is called (see pics). I could not find a reference to it specifically in any parts manual, but maybe that's b/c I don't know how to read a parts manual. I'm going to call it the "maybe this is where you the stuff comes out when you do a coolant flush thingy?"

Note that the first pic is the of the actual bike with the issue, and all other pictures are from the new bike for clarity of the location/part. At any rate, once my scooter pals confirmed that the *"tasteless clear liquid" coming out of my bike is likely distilled water from the cooling system, I can confirm that a) yeah that tank was bone dry, and b) I can fill the coolant tank and over the next 2-3 days it will drain completely.

So, question one- what the heck is this part called?
question two, what's "broken" on it?
question three- is it fixable?

Thanks for all the collective wisdom amassed here! (And for the record, no I'm not riding the bike with a coolant leak.)

That is the drain that lies between the two ceramic seals that separate the coolant from the oil on the water pump drive. The water-side one has failed, and needs to be replaced.

The easiest solution is to replace the whole assembly - I had to do that on my GTS last year.

You need part 1 - 8483785 and part 10 - 840504

I don't think that's even a cooling system part.

I've had to deal with a number of cooling system issues and I have never even seen that part. It doesn't show up in the shop manual as a cooling system component.

See pp. 250 and following of the shop manual:

https://manuals.wotmeworry.org.uk/Vespa/GTS300%20Super/GTS300%20Super%20Workshop%20Manual.pdf

Hopefully someone smarter than me will chime in. I am very curious.

Jimc to the rescue!!!!

Content deleted by tenders. A forum where management/moderators repeatedly quash and delete well-intentioned, constructive concerns about governance issues raised by multiple users does not deserve my participation.

You could also rebuild the pump... but I have no idea where to get the special tool at a decent price. https://www.youtube.com/watch?v=RYj6gr33yaQ&t=1863s

As soon as I saw those parts on the cardboard I knew I'm never going to do this myself. Thanks first to JimC for hitting the nail on the head (as usual), others for the humor, and AnnDee4444 for the video. Should be interesting to see what the book rate is on that!

It's not a hard job to change the whole assembly yourself - and you get to do a coolant change and oil change at the same time.

The engine doesn't have to come out of the scooter, but it does have to be dropped down quite a bit, just as you might have to to change the fuel pump.

I have this issue myself now, what did it end up being? I can't quite follow this discussion. Was it painful/expensive to fix??

With basic tools and moderate mechanical skill levels, its definitely doable.

Just remember that projects like this are a gateway drug. Next thing you know you'll be staring into the bowels of an engine (not too soon, hopefully... )

I just washed my hands from doing this on Ryan's 2011 GTS300. The only real problem is what clamp to use on the small hose coming in the back of the water pump cover. Robot shows a worm drive clamp, no way no how was I able to fit one back there. I did but it was blocking the removal of the timing mark plug. I removed it and used a 1/2" irrigation pinch clamp. They are good up to 150 psi. I crimped it with some end nips I have for pulling nails.

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That's a very good tip for those attempting the water pump change. Mine has worm drive clamps to all 3 hoses. My problem has always been removing the hose in order to do a coolant change. The last change I did I could not remove the rubber hose however hard I tried. In the end I just removed the water pump cover by removing the 3 screws. What is the secret to getting those hoses off?

^^^Getting a metal pick between the hose and the spigot.

I just did a complete cover replacement on my 2007 GTS and I did not remove the hoses, just the 3 screws and used a bungee cord to hold it away. Also I did not lower the engine for access to the top 2 bolts, it was a bit PITA but I got it done.

Robot's video from scooterwest was well done and helped with a couple little tricks like using some sealant (just a little) to keep the gasket in place.

I tried that but I came close to piercing a hole in the rubber hose. Next time I'll try using heat, either a heat gun or pouring hot water over it from a kettle?