take your thermostat out and you can do a home test to test your thermostat. tie it to a string and put it in a pot and slowly bring the water to a boil it should open. it it opens then its not your thermostat. make sure it fully opens though not just semi open. and if it opens. pull the waterpump out and check that. there is not really any way to tell just from inspecting it unless the fins are deffinitely broken but a major problem on the bwm water pumps are the inner bearings break and there is not really any way to tell. sometimes there will be a pressure release hole on the side of the pump that will break when the pump is bad. but mine went out and i had to just get a new one. you may want to replace your temperature sensor. because a bad sensor would be giving your computer the wrong information and may be part of your problem with running bad when its cold. its a five to ten dollar part so not too bad
Last edited by pyromaniac941; 12-17-2008 at 12:26 AM.