Where is the thurmostat on a BMW318I 2003 series thanks

behind the inlet manifold

fairly easy. Remove the indicator first to expose the bottom crew. remove the platsic plate on top of the radiator. it will reveal one more bottom screw. All up 4 screws. 2 in line on the top, and 2 on the sides. They are all 8mm.

HI HAVE YOU PUT THE THMOSTAT IN A BOWL OF HOT WATER TO SEE IFF IT IS OPENING PUT SOME STRING ON IT AND LET IT SOAK IN BOILING HOT WATER.YOU WILL SEE IF IT OPENS .IF IT WONT IT WANTS REPLACING..THEY HAVE WAX INSIDE AS IT MELTS WITH THE HEAT IT OPENS UP.

LOOK UNDER HOOD OF CAR AT LOWER FIREWALL ON PASSENGER SIDE.

Thanks for choosing FixYa and welcome.

It's either a fuse or connections have fallen off rear of lighter (only 2 connections on rear - Hot (center) Ground (side connector)

It's located underneath the car, not in the engine compartment, right next to the fuel pump. It's on the driver's side, right behind the front tire underneath a little panel that unscrews w/ a 1/8mm socket. Make sure you get the right filter.

white smoke is caused by coolant leaking into the cylinders. This comes from either a cracked head, or blown head gasket. You're probably also experiencing a slow, steady loss in coolant as well, and in some cases, you may find oil in the coolant, though BMWs don't always do so. It will often happen after it's overheated for some reason, but is not always the case. You need to get your car checked out right away, as this can damage your engine significantly in a short amount of time.

BMW318i are a bugger to find some of these faults, but there is a set of fuses,on drivers side under dash.there is also another set under the bonnet and also the relays are also under the bonnet and in the car as it could be a relay problem..
Or it could be a sensor on the temp switch and or on the aircom sensor or relay so get them all checked out'.
Let me know how you go RON

Back bleed it with a syringe.