wacko B) as i said before m8 if you cannot hear the run on pump,lift bonnet locate said item and feel to see if its working,if not then the booster will spool up/down,as it will only heat the portion of coolant within the booster itself(coolant isnt being pumped round)then it will get to temperature and then shut down,the fix with very clear instructions on how to fix your pump can be found in the faqs. have you read the war and peace thread on booster heaters?if not set aside a few hours m8,much info within that thread. from what ive read if a new plug is fitted then you will get lots of smoke until all the old crud has been burnt/cleaned off,i get no smoke from mine and that was a new unit fitted about 3 years back. GM,welome to the forum do you get a GOOD DISCOUNT ?? ;) :P