Radiator drain valve

Rusty McNeil · Mar 3, 2007

OK, I have a question...

On the little water manifold underneath the radiator there is a little hex headed plastic valve that is called the drain valve...I think it changes the way water circulates depending on the position it is in.

The manual tells about it and it's uses but doesn't tell you what the hell is closed or open and the markings on it make absolutely no sense (At least to me!)

There is a little spring loaded ball bearing detent on this thing that can fall into one of two holes to indicate precisely the two positions.

Mine is currently in the hole that would be at 10:00 if your looking straight at the thing from the front.

Is this right?

Where are yours at for those of you with newer bikes that have never beem messed with?

Thanks!

Rusty

Buster Hymen · Mar 3, 2007

Ah yes the mysterious drain position! Here is a cut and paste off one of the lists...

If the metal ball is in top window of the valve housing, it's in the
drain position. If it's in the bottom window.....normal operation

.. and there is also this view

It does not matter which position it is in when you are running the
bike.
In the open position it has a small bypass of the thermostat to allow
draining. If you leave it in the open position while riding it only
slightly delays the motor from reaching normal operating temp. no harm
done.

If you play around with that valve too much you can expect it to start
leaking.

Hope that helps!

maleko89 · Mar 3, 2007

Rusty, if it's in the top hole it's the drain position. Bottom hole is normal running. Basically when the it's in the drain position a valve is opened so that the radiator is drained. I don't think the late model vmaxes are any different. Next time you change your coolant, turn the valve. If the draining of coolant speeds up that's the drain position. If it slows down that's running position.

Rusty McNeil · Mar 3, 2007

Thanks guys,

I have been running mine in what is apparently the drain position for about 1 year since I did cooling system maintenance.

Apparently with no ill effects. I was worried if somehow it might effect cooling to certain parts of the motor like heads or whatever......

Mine did weep just slightly a few weeks ago but has since stopped.

Guess I'll close it now....

maleko89 · Mar 3, 2007

When putting a new o-ring on the drain valve, put a dab of vasoline on it. It won't leak.

When you keep the switch in the drain position you are bypassing the thermostat and coolant is running through the radiator even when cold. Once the thermostat opens, it runs as normal.

Rusty McNeil · Mar 3, 2007

No wonder it takes so long to warm up.

The engine temp has seemed rather "ambient dependent" also, although never running hot definetely running way cold when temps are down low outside.

Thanks, I'm gonna tend to this tomorrow....