Basic question: On a B21 engine, when refilling with coolant after draining the system, is it necessary to loosen the thermostat housing to let air out as you fill? Or is it OK just to fill the system up through the reservoir tank, then start it up and monitor the temp gauge while the engine warms up to operating temperature, adding coolant as needed. Which is actually the recommended procedure? I have visions of the head having no coolant in it as it gets too hot waiting for the thermostat to open, but I guess the temp gauge would show this. Am I worried about nothing here? Is the engine safe without opening the thermostat housing to "burp" it as long as the temp gauge in the instrument cluster doesn't go above half way and the system has nearly the recommended coolant volume before starting? What are your opinions on this??
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Thanks for all the help. DougC 1981 242, Turbo bars and wheels, M46............1993 245, B230 NA L-Block, M46, Turbo bars.