Hi, I'm new to the forum so advanced apologies if I sound off track.
Basically I'm constantly getting cold air through my air con / fan heater on all air vents.

I have a 118i n46 55 plate all is fine apart from the air con/heater.
The engine temp runs around 100 degrees +- a few.
Engine temp is the same if out side temp is high or low.
I have noticed when its warmer I need to fill the coolant more regular than when its cold not sure if this is linked to anything.


However my heater is always cold out of all air vents except the centre left. This will put out some warm air only when all other vents are closed
and gauge are on max it only comes out hot when the air con / fan has been turned completely off for x amount of time and even then it won't stay warn it comes out for like 10 seconds warm then goes to cold again.

it will give out more heat and warmer heat if I completely turn the fan off for a set time so the longer the fan is of for the longer I get bit of heat for out of the centre left air vent but even then it goes to cold.

I'm told to look at the matrix/temp gauge/or check for air in rad and engine coolant.

I was after a 2nd opinion on this or if anyone else has had this issue before I buy the parts or try to diagnose.

thanks for any help in advance