Coolant/radiator system?

[oracle]

I brought a VTR a few weeks ago, found it was overheating a bit and yet there was still enough coolant in the overflow. However when I took it in for a service, the guy said it was low and topped it up. Since then it has been peeing coolant through the overflow hose after rides (about 8 times). I took the tank off this morning to look at the radiator itself and despite the overflow reservoir being more than full, upon opening the radiator cap I could not see any coolant. Is my google research right in that this should be completely full? And I therefore really need to get onto this? Any suggestions? I can do some basic maintenance but my last bike was aircooled and I am a) disheartened that this problem wasn't picked up when I paid for the mechanics to have a look at it and b) really don't have the money to pay for professionals to do the work atm

[bluebird]

Is the fan working?

[FJRider]

Check the tube to the coolant reservoir has no leaks (or blocked)... ie: NOT sucking air.

As I understand ... when hot it pushes water out of the radiator to the reservoir, and as it cools ... sucks it back to the radiator.

[oracle]

Check the tube to the coolant reservoir has no leaks (or blocked)... ie: NOT sucking air.

As I understand ... when hot it pushes water out of the radiator to the reservoir, and as it cools ... sucks it back to the radiator.

That was my understanding as well. Which is why it makes sense that if overfilled would be peeing the coolant out of the overflow hose. However if blocked, would it not have that happening so wouldn't be doing so? And if there were holes in the line wouldn't it be leaking from there (which it is not)

[oracle]

Is the fan working?

It is not overheating any more, stays at about 1/4-1/3 temp when running now and they checked the fan was going when it was serviced etc

[FJRider]

That was my understanding as well. Which is why it makes sense that if overfilled would be peeing the coolant out of the overflow hose. However if blocked, would it not have that happening so wouldn't be doing so? And if there were holes in the line wouldn't it be leaking from there (which it is not)

Water (under pressure especially) takes the easiest route ... obviously not blocked, but as the engine cools (gradually) it sucks it back into the radiator... if it sucks a little air too, it may result in less water in the radiator each time it cools.

Just ensure the outlet FROM the radiator (inside the coolant reservoir) is below the water level in the reservoir at all times ...

[NinjaNanna]

Radiator cap is actually a 2 way valve. Check to make sure it isn't jambed shut in the "suck" position. If it is then it will be able to push the expanding water out, but not suck it back in as it contracts while cooling

[oracle]

Radiator cap is actually a 2 way valve. Check to make sure it isn't jambed shut in the "suck" position. If it is then it will be able to push the expanding water out, but not suck it back in as it contracts while cooling

How am I supposed to do that? the water doesn't exit to the reservoir via the cap in my bike's case though, the hose comes out further down

[FJRider]

ALSO check the thermostat ... done by taking it out and seeing if it's completely shut when COLD ... Put it in a pot of boiling water and make sure it OPENS FULLY...

Not opening fully will cause overheating too ... (usuall shown up by heating up on the gauge quite fast)
Not closing will make it run cold, or take ages to heat up.

If it's (the cooling system) working properly (well at least seems to) Keep a close watch on the fluid levels before/during/after ... use. (If its working ... dont fuck with it) and go from there, regarding the symptoms you find.

[oracle]

ALSO check the thermostat ... done by taking it out and seeing if it's completely shut when COLD ... Put it in a pot of boiling water and make sure it OPENS FULLY...

Not opening fully will cause overheating too ...

It is not overheating anymore, was only overheating because the radiator was low on coolant which it may be heading to now. The only problem appears to be that the coolant isn't returning to the radiator from the overflow reservoir

[FJRider]

The only problem appears to be that the coolant isn't returning to the radiator from the overflow reservoir

Then it would seem the return hose IS THE PROBLEM.

REMOVE it and check for leaks and all seals, are sealing ... and the end of the return hose is ALWAYS below the water level.

[oracle]

Then it would seem the return hose IS THE PROBLEM.

REMOVE it and check for leaks and all seals, are sealing ... and the end of the return hose is ALWAYS below the water level.

I will have to try to find time to do this (and figure out how) but I still have the question that if it was leaking or not sealing, would the coolant not be coming out from here when hot?

[FJRider]

I will have to try to find time to do this (and figure out how) but I still have the question that if it was leaking or not sealing, would the coolant not be coming out from here when hot?

NO ... as I said in an earlier post ... water takes the easiest path. The hose to the coolant resevoir is NOT a pressure line. So leaks are NO ALWAYS obvious ... Clamping the reservoir line end and idle/run to increase engine temp may show where the problem is ...

A temporary solution is topping up the radiator prior to rides.

[oracle]

NO ... as I said in an earlier post ... water takes the easiest path. The hose to the coolant resevoir is NOT a pressure line. So leaks are NO ALWAYS obvious ... Clamping the reservoir line end and idle/run to increase engine temp may show where the problem is ...

A temporary solution is topping up the radiator prior to rides.

OK mate, calm down I'm fairly new to motorcycling and very new to any sort of mechanical stuff and just trying to understand, hence asking for HELP

[oracle]

Thought about it more and looked into how radiator caps work (as I said, I am very new to thinking about the mechanics of a vehicle) and it is a possibility that this could be stuffed. Is there anyway I can check this myself (without the special pressure equipment) or how much would a replacement one approx be?