i would burp your cooling system and ensure that all is up to spec... last thing you wanna do is fix a hg and be a little low on water or a little irregularity and go racing and have it go ping!
park car on hill or jack up so radiator is at highest point
pull radiator cap (make sure car is very cool)
get bottles of water
start car
turn heater to hot and switch on to full
as it warms up and thermostat opens you should start seeing a few bubbles
as it is warming top up the radiator till bubbles are down to a minimum or none at all
when you think system is purged, cap the radiator, turn car off... let it down
see if you can still hear that odd bubble
there is a short shifter for sale in the for sale section i believe
also can be found on ebay
good luck at the drags
