RE: [ST] Cooling and Fan

["Dan Wallander" <triumph99@xxxxxxxxxxxxx>]

Jill,

Your fan is coming on after turning the engine off on hot days because
there is no air flow through the coils, but the heat is still there.  Even
though the pump isn't moving the coolant, convection will continue to move
the coolant through the system, though slowly, as long as the thermostat is
still open.  Any vehicle with an electric fan will do this if the coolant
is hot enough to turn the fan on and the system is set up to leave the
power on to the fan circuit.

As far as the coolant taking only about 2 quarts, that's about right if you
drain from the head drain port.  You're right that the lower hose, the
coolant pump, parts of the engine and the overflow catch tank still hold
about a quart of fluid.  The catch tank holding most of it.  Draining from
the lower hose probably doesn't get that much more out, won't drain the
catch tank (which is behind the plastic near the passenger seat) and you
have to remove the lower fairing to do this.  I don't think it is really
necessary to get all of the fluid out on each change as long as you change
the antifreeze near the recommended intervals.

Dan

Dan Wallander
Albuquerque, New Mexico
www.danwallander.com 
Triumph Sprint ST :: BMW R90/6
TSRA-VP, ABC, IBA, AMA, HSTA

> ;-) I've got a couple of questions. One has to do with the radiator fan.
After 
> any prolonged low speed cruise through town, my bike heats up to about
1/3 on 
> the temp gauge and the fan comes on. After I turn the bike off (with the
key) 
> the fan will start up and run for a while. Why does it do this? The water 
> pump isn't moving coolant through the engine so I can't think of any
plausible 
> reason. Inquiring minds....
>
> Secondly, I recently did a coolant flush on the bike. I bought a service 
> manual and religiously followed the instructions...remove drain plug,
loosen 
> radiator cap, blah, blah, blah... once most of the coolant had drained
out I tipped 
> the bike over to get the last bit out. Then I got the thing back together
and 
> refilled, but it only took about 2 quarts vs. ~3 quarts stated in the
manual 
> after bleeding out the air. After sitting there one day for a while and 
> studying the layout of the engine I got to thinking...why couldn't you
just remove 
> one of the hoses at the bottom of the engine (like to the water pump) and
drain 
> from there? It seems like it's a heck of a lot lower point than that
drain 
> plug up on the side...???
>




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