Modern Vespa

I don’t like to use the word never, or deal in absolutes, but I’ve never seen that gasket fail on the H2O side, or there.

Top, yes. Bottom, yes. Ripped or jacked or improperly installed, yes. But all those times, oil leaks.

So 6 keeps the oil in the case, 8 keeps the water in the pump.

But it’s weird, symbiotic relationship. 6 & 8 have to work together.

8 is Sam and Dean, 6 is Cass. The coolant is Lucy and the oil is Rowena

But I digress....

Anyway, the pump side ( of the seal is, in essence, two parts- interior and exterior. The oil side (6) is a standard double lipped viton spring seal, which is common for this application. Great at keeping things in not so great at keeping things out.

So, interior of eight breaks down and the system pressure pushes the aguas into six and presto! Milkshake time.

Or something along those lines.

hth

-g

Last edited by greasy125 on Sun Nov 22, 2020 5:53 pm; edited 2 times in total

If that's what has happened, why is there no sign of leakage from the weep hole this time? I just can't see 'no weep' existing alongside 'seals gone'.

That's sorta where I'm at too.


Bowing out now....

exactly. the leakage from the weep should go hand in hand with this type of failure. but, i've seen it a few times both ways. suspected headgasket only for it to be waterpump and suspected waterpump only for it to be headgasket.

if it were headgasket, pulling the plug might give some insight.

ultimately, without hands on the bike it's hard to say for certain either way. both are common failures, both can exhibit the same way.

-g

Thanks again, for the info.

Wondering about my next move? Checking the plug? It would help point me even more strongly toward the pump.

Greasy, you mentioned pressure testing for the pump. Is that the definitive test? If so, it's off to the mechanics. I have Robot's video on waterpump queued up, just haven't had time to get far into it......

Sort of a side question, as I didn't totally drain the oil, do I want that mess out of there ASAP, or won't it hurt anything?

Pardon my ignorance, but would you mind telling me where this is located? Obviously if it was "weeping" I'd have seen it...I think....

There you go.....

GTS GTV Water pump weep hole

You forget that when the engine is running, the pressure inside the crankcase increases, helping to increase the thrust on the seals...

I may have scrolled past but there is obviously water in the oil. Have you looked in the coolant recovery tank to see if there is oil in the water?

There is also a sniffer to see if there is combustion gasses in the oil or water.

I have a cooling pressure tester for cars and it can find leaks that are otherwise hard to find. Pump it up and wait for the drips. You would have to rig up some kind of adapter. Get an extra coolant recovery cap, drill and tap with 1/8 pipe thread and put a hose barb fitting in it.

Good luck.

Aha, one more thing to do as I go down the rabbit hole! But thanks, I was curious how it could be done.

I did peek in the coolant reservoir and all seemed copacetic....

I guess part of the process is trying to decide whether I want to even mess with things at this point....still haven't seen Robot's video. If my eyes get too big, I may just ship it out.

Thanks for that...I guess I'd run across it before, but well, wasn't all that important at the time.

I too don't see the connection with weeping and seals leaking coolant into the crankcase...but hey, I'm learning here....

Osmosis..?

Wasn't he the Roman god of seepage?

+ or - ...

No, but really cold and can cause condensation to build up on short trips where the motor doesn''t get up to full temp for long enough.

Okay, finally had a chance to look at the scooter again. Greasy, you'd said you'd want to see the plug, so pulled it for a look-see.

Big hands can be useful for some things, but not so much for exploring the bowels of a Vespa. At least I didn't draw blood.

Looks pretty clean to me. Guessing that helps rule out head gasket/cylinder head issues? Or not so much?

FWIW, on an earlier inspection, found some smeary stuff on the top side of the water pump. As I had just bled coolant a couple of weeks earlier, thought it could be residual of that...not sure how long that hangs around, or if a leak would even manifest on the top vs the bottom. But hey, i'll throw it in as potentially useful

IMO, change the oil and oil filter several times to clean it up, and ride the bike a lot. Keep close tabs on the coolant level. If problem doesn't appear again, you weren't riding the bike enough to heat up the engine and oil to drive water condensation away.

As a rule, people don't ride their Vespas enough and since you have three of them, that rule probably applies to you, triple time. Here in the U.S., motorcycles are typically ridden 3000 miles a year and Vespas significantly less so. Kind of astounding when you consider how well built Vespas are and the mileage some people rack up on them.

The drawing if it is accurate
#8 is the seal between the coolant & the crankcase
A motor that hasn't run for some time will have the seal fail

Which brings me to the question floating in my mind...if there are no visible leaks, plug looks great, what are the chances of it simply being condensation....oil does look like there's more than just condensation in it, but I don't know that much on the subject. I'm a bit skeptical.

FWIW, one of the scooters gets very little action as it's nominally my wife's.
The GTS has had a relatively quiet year, but still has a couple thousand miles over the summer, though mostly short commutes of 6 miles/15 minutes of running.

Joining the conversation late, and I totally think head gasket/pump/freeze plug.

As far as the condensation theory, how much coolant is in the reservoir? Topped off from your last service? Little low? MIA?

Just did coolant change a few weeks before, most likely put it at the full level, and currently its above the "low" level. Of course I wasn't expecting to be checking for loss, so it's just to the best of my recollection.

I had a water pump fail after I hadn’t ridden my 2012 GTS for ages. The oil looked the same when I pulled the motor down. Given you have cappuccino oil with your oil container half full that is a lot of condensation in the engine. I would have thought condensation would be a smaller amount of cappuccino.

Agree with Rallygeek that it's too much water for condensation.

Yeah, likewise. Gut feelings that's way too much.

Well, after ruminating about things for a while, and seemingly I have no way to differentiate pump vs. head gasket, it doesn't seem like I have anywhere to start.

So off to a shop. My dealer, like others, seems to have gone belly up, so time to look for alternatives. There's a shop that's actually closer (one hour), so just called them, and it seems they'd suggest waiting until March or so, when they could test drive it after repairs without frostbite. Makes sense to me, but I don't like the idea of sitting on a crippled scoot over winter, even if it's too cold to ride it.

So, if anyone was waiting by with a big bowl of popcorn, y'all are just going to have to wait for the verdict.

Back in spring!

Bugger. The popcorn will be past its use by date by then.

i don't know what your workshop situation is like, i mean, i know it's balls cold up there, but if you can endure and work with a little heater it's really not that hard of a job if you've got a lift. you can order a complete pump housing ready to go and just R&R the whole thing in a long afternoon.

granted, riding season is kinda done for you and all that, but this is really something that you could tackle and be back up and rolling and ready for spring when it comes barreling in.

it's not a big pile of money to bet on the waterpump and just be done with it. the head gasket is a little more involved and a solid 8ish in the pain in the ass department. but again, the stakes are super low in that a new gasket is only a couple of bucks.

just a little food for thought.

-g

I tend to agree. Water pump is pretty simple to do as long as you have a heater to keep warm in the workshop.

Nah, it's obviously a kitchen table job.

Are you going to spend the winter wondering if there's any little pockets of water left inside the engine rusting away?

I certainly wouldn't leave it without knowing there was zero chance of water in the wrong place. The chances of some corrosion crises would be too high.

I'd drain all the coolant, and drain all the oil, then fill with oil with a new filter and run it for 10 seconds *with no coolant in it*. That'll get the right bits lubricated with hopefully zero water contamination.

Then come the warmer weather you can change out the water pump or do the head gasket.

So I'm thinking this would be an appropriate use of Shell Rotella T6 or other similar, cheap oil.

It's what I'd use.

You guys are just the worst enablers. Hold that popcorn!

And of course you know deep down I want to get my hands on it....

Okay greasy, first off, thanks for the encouragement. It's cold and all, but throwing some heat would make things workable...I have our garage, and even had a thought of putting up some kind of plastic film enclosure if necessary. I've got the tools, and the lift....

So, it sounds like water pump is the chief suspect? Or just the best place to start? I'm guessing there's no guarantee, but the relatively low cost of the water pump, lesser and free (lol) labor makes it a reasonable risk? So that being done, if the oil goes funky again, we're on to the head gasket?

So for the moment, it's get the fluids out, oil replaced...reading between the lines, jimc, I'd assume that coolant isn't important for 10 seconds of running?

znomit, are you trying to get me un-married? Reminds me of my buddy in college, who'd inherited a VW minivan from his grandparents and decided to work on the engine on his coffee table. Made a great conversation piece.

So, thanks for the input, all. Off to buy some Rotella and price water pumps......

Oh, and while I have your attention, thoughts on just doing a water pump rebuild? Is it enough of a PITA that I'm better off with a complete unit?

You know, this little paranoid voice in me says you're all just bored and with nothing to do in cold weather (znomit excepted) you can think of nothing better to do than encourage some doofus to dismantle his scooter....but naw, I still trust you...for now.

Running the water pump dry for even a short time can damage it. The coolant is also a lubricant.

Umm, yeah, makes sense. On rereading jimc's comments, I'm thinking the "with no coolant in it" remark was about the contaminated oil. Not sure I'd need to drain coolant...yet...if it's clear.

It is less hassle to just buy the pump and casing. Depends on what your skills are and what tools you have. There is a good Robot video on it.

I think I'm far enough in to cut some corners. Did see the Robot video. Of course everything looks doable on YouTube.

Funny, my first thought on your mention of skills was ""Skills? We don't need no steenkin' skills..."

https://www.youtube.com/watch?v=e1lyNt5km8U

Make it easier on yourself and setup shop in the family room.

An oldie but a goodie.