Honda VTR coolant boiling ?

Recently on two days over 37 degrees when stopped at the end of a trip
the coolant from the overflow bottle on my Honda VTR 1000 overflowed (I
suspect it boiled from the temperature from the surrounding engine).
There was no problem with the radiator and it didnt boil over into the
overflow coolant tank. . I think it is purely from the location of the
coolant reservoir between the cylinders of the engine. Has anyone elso
had this problem.
Phil

 

What makes you think the water in the plastic bottle external to the
engine would be hotter than the water inside the engine where all the
heat was being generated?

Nev..
'04 CBR1100XX

 

No water escaped from the engine / radiator. The coolant tank has an
overflow hose at the top with nothing to stop it escaping. I am only
guessing at this stage though.
Phil

 

I believe Nev is trying to say.
It came from the radiator....ie. It was doing it's job.

justAL

 

No it didnt come from the radiator. The coolant bottle emptied. The next
day I had the bike serviced and the radiator was still full. Surely if
it had come from the radiator its level would have dropped. The Honda
dealer had no real answer.
Phil

 

So you're saying it was pissing out of the overflow?
Can you put a figure to that? 150ml, 500ml?
How much was in it to start with?
Can you put a figure to that?

It can still leak out of the overflow and not present a significant change
in level.

Just because there's a puddle of fluid under your bike that's 2 feet square
doesn't mean that what's left has dropped below the minimal service level

justAL

 

In 4000 km of travel lost no coolant. Two v hot days and lost whole of
contents of coolant reservoir. Only observed between 1-2 square feet of
fluid on each of two days when stopped. Some could have escaped during
slow travel before stopping. Temperature gauge was within normal limits
at all times.
Phil

 

I'm yet to own a single vehicle, car or bike, that doesn't have some coolant come out the overflow pipe on really hot days.

Bear in mind that the coolant will heat up when the engine is switched off before cooling down.

 

It's a sealed system with only one overflow point. When the engine
overheats, the water expands from the radiator into the coolant overflow
tank, the plastic bottle. When that is full it overflows. i.e.. When
you see the overflow tank overflowing, it means that the cooling system
has overheated. When the engine cools, it will draw the overflowed
water back into the radiator from the overflow tank. With a cold
engine, take the radiator cap off. If there is no water in the overflow
tank it probably means that the radiator will need topping up too. If
there is water in the overflow tank and the radiator is full it means
that probably a small amount of water overflowed, probably need to get
the cooling system checked out. If there is water in the overflow tank,
but the radiator is not full, you REALLY need to get the cooling system
checked.

Nev..
'04 CBR1100XX

 

So what your saying Nev is that water expands when heated?
Interesting...

 

The answer should've been "that's 'cause it sucks it back in when it cools".
That's what the "overflow" is for: it hold the extra that doesn't fit in the
cooling-system when it's all expandified.
When it's coolificated again it sucks some back in (otherwise it'd collapse
your radiator)
--
Clem

--
Clem

"If I don't answer you, it's because I believe my point has been made in the
current post or others on the subject or that the points of argument
presented are illogical." ..... Toosmoky

 

Eh?... The WHOLE contents of the reservoir?!!?
It's not much of a reservoir if it didn't keep some in "reserve" then is it!

 

It also expands when cooled below zero!
[cue Twilight-Zone music]

 

It must. How else could a pressure cooker work?

Nev..
'04 CBR1100XX

 

Make sure that your thermo fan is coming on, and possibly check that
your thermostat and temp sender are working correctly.

Also, how many km has the engine done? I started to get similar
symptoms from my GPX250 at about 120,000km when the rings were getting
worn.


BTH

 

Not since I replaced the water pump that had no vanes left.

(Thanks to the mech that cleaned the running pump with a screwdriver...)

 

Ditto.I think there is a fault in the temp sensing system and or the
bike,"IS" overheating.I'd suspect a stuck or partially stuck
thermostat for starters.

Note:Most Honda/bike thermostats are stock parts and can be bought
from local high street auto discount shops for way less than
Honda/bike makers charge.Take thermostat into shop and ask(Don't tell
them what it's for ;-)

 

Hi Phil, as the coolant heats up it expands a bit and pushes some out of
the radiator into the coolant overflow tank. When the coolant cools down
again, it contracts and the radiator slurps coolant back out of the overflow
tank.

-----sharks

 

I thought pressure-cookers worked by preventing boiling by limiting the
expansion.
i.e. It still gets hotter (and expands) it just doesn't turn to steam.