Coolant leaking from vent

[kaiq]

My bike is losing coolant. Recently, whenever the bike is hot, there is always some coolant seen flowing out from the vent. My coolant bottom is at the right side, whereas the vent is located at the left side on the engine itself, facing up, feels like a hole, near the gear shifter. There is no cap covering it, so I assume it's a vent for pressure or something. There is no leaks at any pipes above. If got, I would have seen the trail of redish/whitish stain left behind. Currently only seeing redish/whitish marks left behind.

 

So far, it keeps of losing until the coolant reservoir hits the min. mark. If top up, it will leak until min. mark again.

 

What could be the problem? It only started recently. My coolant is the Shell coolant. It's red colour.

 

In the pic the red circle shows roughly the location of the hole. Borrowed pic, so not my engine.

http://img155.imageshack.us/img155/7743/cool3xn7.jpg

[DM]

are you riding a V-twin/ V4 engine ? are you sure it's a vent?

[WildCard]

Is it a weep hole?

 

I had a similar experience of coolant leaking out from a uncapped hole on one side of the engine, near the water pump.

Did a research and found its called a weep hole. Its sort of a safety feature where if the rubber seal that seperates the oil from the coolant in the water pump is breached, the weep hole will leak the coolant out to prevent the coolant from mixing into the engine oil.

 

NB: This was like 2-3 years back. A recommended fix was to have a mech look into both water and oil pump and check the seals (not gasket).

 

You might want to have a mech look into it.

 

What bike are you riding, BTW?

 

 

*Update*

Found some old threads. Hope it helps:

 

http://www.tlplanet.com/forums/showthread.php?t=74570&highlight=weep+hole

 

http://www.tlplanet.com/forums/showthread.php?t=69439&highlight=weep+hole

[kaiq]

I'm riding a v-twin. So far have some advice to change the radiator cap. Done that, tomorrow testing result.

[kaiq]

So far changing the radiator cap works - no leak seen again. I think it's the weep hole that is leaking the coolant, cos it's quite near the pump.

 

My bike is VTR250.

[kaiq]

Unbelieveable... I found my own problem's solution (problem happened again, forgot solution) after 8 years... It's good to keep an archive!

[kaiq]

For the record, the main leak source is not due to radiator cap - it's a worn out o-ring at the water pipe. So bought a o-ring from local o-ring store and changed it.

 

And no, the water pipe wasn't cracked