Thread: Coolant vent
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Old 10-10-2003, 03:01 PM
Duke2.6 Duke2.6 is offline
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Join Date: Mar 2003
Location: Southern California
Posts: 2,055
I would not recommend opening the "vent screws". There is a vent line at the top of the thermostat cover that routes to the expansion tank, and any air in the system will eventually bleed, but it may take two or three cycles for the system to completely self-bleed.

Fill the system slowly and when it won't take anymore install the cap loosely and start the engine. Set the temp control at "max", to open the heater control valve, but leave the fan speed at low if you have a manually controlled fan. Observe coolant level as it comes up to temp. (It helps to block the throttle up to about 1200 revs.) The coolant level may rise before the thermostat opens, but once the thermostat opens the level will usually drop. Add more coolant as required to bring the level to near full.

At this point install the cap all the way and drive the car briskly for a couple of miles, then check coolant level and fill as necessary. At this point you're done, but check the coolant level after the next several cycles and fill to capacity as necessary. Also, during the next couple of cycles increase the temp setting to max for a while to ensure that the heater control valve opens so coolant flows through the heater core and purges any remaining air.

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