sfisher@megatest.com (Scott Fisher) writes:
>Bleeding (sometimes called "burping" in this case) the cooling
>system is a way of ensuring that no trapped air remains in the
>passages. To bleed most systems, you need to run the car till
>the thermostat opens -- which you can tell by feeling the upper
>radiator hose. When it's hot to the touch, the thermostat has
>opened and you can begin.
>et cetera
Sometimes the configuration of the water passages and the location
of the thermostat prevent the newly added coolant from reaching the
thermostat, and the thermostat thus is only in contact with air. As the
engine heats up the air prevents the hot coolant from reaching the
thermostat which as a result does not open until the air becomes hot
enough to open the thermostat. During this phase the temperature gauge
will be in the red. You will know when the hot air finally opens up the
thermostat by the sudden drop in temperatureand in coolant level.
Of course, this is somewhat unnerving as engine temperatures may
locally (albeit briefly) exceed the design specs.
The remedy is: (1) drive around on a bumpy road with the heater full
blast for extra cooling and hope that the bumps will help in getting rid
of the airlock; or (2) put an aspirine in the thermostat to keep it open
and prevent the air lock. The aspirine will harmlessly dissolve in the
coolant after it starts flowing. I guess any type of dissolving
solid would work as long as it does not leave any significant residue.
Dirk de Boer
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