STILL with the overheating! P250

[wordslinger]

..maybe so, i guess...you'r getting a small amount of air /gas into your coolant system that makes the coolant boil...

[jprestonian]

Hoo -- I'll do that. Does the overflow tube extend almost to the bottom of the overflow reservoir?  That would make sense, in the physics-sense, I reckon. I'll make sure to check, but I seem to recall the overflow being half-full, every time...
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[Hoolander2]

yeah, I remember you said you did do a pressure test on the radiator and it was ok.  But that doesn't rule out the reserve hose or, for that matter, the cap. 

[Hoolander2]

Wow, these posts're coming faster than I can keep up! 

Well, if my little theory is right, I guess the reserve tank level would go up a little bit over time, though, maybe not. 

[jprestonian]

..maybe so, i guess...you'r getting a small amount of air /gas into your coolant system that makes the coolant boil...

I don't think it's so much a "boiling" problem, as that would tend to make it spew coolant into the overflow, and possibly out the puke tube -- none of which has happened, ever. A small bubble of air/gases in the system however would tend to explain the temp gauge's behavior -- not throttle-dependent (unless riding at high speed, continually), and even when it hits full HOT when stuck in traffic, a hop up and down on the seat can cause the needle to plunge 20% or more (perhaps causing the "bubble" to travel along, rather than sitting right by the thermosensor).

That's why I was theorizing on it being a tiny breach of the gasket. When I burp it every couple of weeks, I never have to add more than 3-4 oz. of coolant back into the system. Right now, if it is a gasket leak, it seems to be very, very small.
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[Hoolander2]

YEp, and that bubble could just be air with coolant steam in it. 

[wordslinger]

..i admit, i need to research your scoot's system before i could give a better educated guess...

..all these theories seem relevant...just pinning down the cause....

[jprestonian]

Hoo sez:

YEp, and that bubble could just be air with coolant steam in it.

I appreciate everyone's thoughts on this, and I will make sure the reserve tank is where I expect it to be (around half full) before I go tearing the jug off this mother.  ;)
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[wordslinger]

..no doubt....check the integrity of th hoses too, i reckon...

[Hoolander2]

Yes, the hose goes into the reserve tank below the level of the fluid.  I'd even check the nipples where the hose attaches at either end for tiny cracks.  A good ole visual and manual inspection is in order! If not outright pre-emptive replacement.

[jprestonian]

Worst case scenario: I now have a very kick-ass lookin' head gasket (that I hopefully don't need, just yet).  ;)
.

[wordslinger]

...good luck jp....but your scoot's history in this matter preceeds...

 

[Hoolander2]

Would be nice indeed to have a beautiful, not needed head gasket to hang on the wall. 

[wordslinger]

..i got a brand new, 1 mile used, kevlar belt with a nice 1/8th inch deep groove in it on my wall..


..dammit...

[Hoolander2]

LOL