Stupid question but after replacing the engine in mine a SECOND time I don't mind sounding stupid. Whats the best way to bleed the system ? First proper run after new engine and running just above normal. Replaced relays to be sure, car running now in drive for two hours, fans cutting in and out as usual. Occasionally getting bubble up the front pipe into the expansion tank. Should I drive with radiator cap loose for a few days ? Or something else. Thanks, Mark.