Simplified cooling system bleeding after thermostat replacement

["ksgrimsr" <knut.s.grimsrud@xxxx>]

Hi Folks,

I replaced my thermostat the other day and thought I would share my 
simplified coolant system bleeding technique that worked pretty well 
for me. Disclaimer: this technique is only suitable for removing air 
trapped in the waterpump area (like you would get when replacing the 
thermostat) and is not sufficient for removing trapped air in the 
rest of the system.

In order to get the thermostat replacement job done quickly/easily, 
I did not empty the coolant from the system and instead just put a 
tub under the water pump to catch the spillage and made sure the cap 
was on the header bottle tightly (to reduce the amount of coolant 
from the bottle that would spill out). When removing the thermostat 
cap there is obviously some coolant lost and hopefully you catch it 
in the tub as it spills out.

After reassembly, I topped off the header bottle with a suitable mix 
of water and antifreeze, leaving the cap off the header bottle.
Using a length of clear tubing (the "clear" part is important) you
can use your mouth to draw out the air through the bleeder nipple on
the thermostat housing. It's important that the tubing be clear so
that you can tell if you're done drawing the air and are starting to
draw coolant -- you don't inadvertently want to consume any
antifreeze. You want some height on your end of the tube in order
to get the best air evacuation effect (you're not trying to siphon
anything, but rather trying to draw a low pressure). Bleeding the
setup took about a minute.

Obviously, those that have the self-bleeder kit installed don't have 
to worry about this in the first place, but I don't use the bleeder 
kits on my cars for philosophical reasons -- I maintain that once 
bled thoroughly, a properly functioning setup shouldn't need it. The 
only time I had trouble with the cooling system on either of my cars 
was when I had the head gasket fail on my one DMC resulting in 
gasses getting introduced into the cooling system.

Hopefully someone will find this little bleeding trick helpful.

Knut