[levine98]

I've got this nagging problem ever since I purchased my 2004 ST3 used in 2006, i.e, leaking radiator fluid or the smell of radiator fluid.

When I first purchased the bike, radiator fluid would leak out where the main hose to the water pump is connected to the radiator if the bike temperature was cold and the outside temp was below 55f. It would stop once the bike warmed up. After tightening down the hose, the issue went away for a while (mostly, ever once in a while it would still leak).

So finally, I swapped out all of the hoses with a set of fancy silicon hoses. Installed them and have not seen a drop leak since. However I have noticed that after running hot the bike will smell sweet, and after running it long distances the reservoir slowly goes down (over a thousand miles and lost about 1/3 of the fluid).

Clearly something is either leaking outright or evaporating slowly.

When I pulled the skin, all of the hoses had a gritty film on them, as if they were sweating? I ran the bike for 20 minutes twice, just to see if anything was outright leaking--no obvious leaks anywhere?

So now I'm thinking that the radiator has some pin prick holes in it that causes the fluid to vaporize around the engine parts? Am I crazy or has anyone else every seen such a situation?

I've had this bike going on 4 years--it would be my favorite bike but this issue--it is driving me to distraction since I can never take it out without being anxious........

Thoughts?

 

[Gearbox]

I would say you still have a leak of some sort but perhaps steam not water ?

Try running the bike without any bodywork until she gets really warm (i.e.Fan comes on) as you may then be able to see what is occuring.

The system , like most water-cooled installations is sealed (hence the expansion tank) so there should be no loss of coolant even under extreme conditions (e.g.trapped in stationary traffic or similar).

The only time I have had this problem (on a car) was when the head gasket blew which occurred only when the engine got really warm and then the added pressure boiled up the coolant and forced steam out of the valve on the header tank)
Is it possible this might be happening ? It might explain the blow-up on pipe connections ext ?

Because everything seems to be picking up a layer of moisture/grit it seems most likely to be steam IMO.

 

[JasperST4]

What about a head gasket leak? Any signs of moisture in the engine?

 

[stryder]

Thoughts?

Coolant is very tenacious in that pools/droplets of it last a very long time and you may be burning up and smelling left over coolant in some recesses of the engine as it heats up and steam would be visible, but the effect of the tank level dropping could mean you may have a bad water pump seal, and the coolant may be leaking into the sump, assuming the rad has been properly burped.

 

[860GT]

Mine leaks when it's cold - in the fall and winter. When the weather is warm, it doesn't leak. I shelled out $46 for a new radiator hose, and it still leaks - not very much, but approximately a quart over the fall and winter. I gave up worring about it. The bike has been doing it since new.

 

[levine98]

What about a head gasket leak? Any signs of moisture in the engine?

Not that I can see. The bike was serviced last year, including a compression test, so I don't think whatever is going on is in the head.

 

[levine98]

Coolant is very tenacious in that pools/droplets of it last a very long time and you may be burning up and smelling left over coolant in some recesses of the engine as it heats up and steam would be visible, but the effect of the tank level dropping could mean you may have a bad water pump seal, and the coolant may be leaking into the sump, assuming the rad has been properly burped.

I don't recall doing anything special when I refilled the reservoir after installing the new hoses. I'm sure I ran the bike to warm, then topped off the reservoir, but didn't "burb" anything....that might explain the "loss" of coolant, but not the sweet smell.

 

[levine98]

Mine leaks when it's cold - in the fall and winter. When the weather is warm, it doesn't leak. I shelled out $46 for a new radiator hose, and it still leaks - not very much, but approximately a quart over the fall and winter. I gave up worring about it. The bike has been doing it since new.

Hear what you're saying, but not wired that way--got to be right otherwise my other 2 bikes think I'm letting my Ducati get away with lower expectations......