Okay heres the deal. Got a 00 323i and recently ive been smelling something coming from the heating system. Friend said to check if theres a leak. We found a leak in the tub that you poor the antifreeze into. We drained the system and patched it up. Filled it back up and now the service light came on, cold air is shooting out, and the temperature on the gauge is rises near the red point. Im going crazy now and cant figure out what could have happened? The tub is not leaking anymore though so dont know what the problem could be. Any ideas? What should my next step be? Thanks.

Sound likes you have an air pocket in the cooling system, or still low on coolant. You have to bleed it out, there's is a bleeder valve/screw somewhere up front, be careful they tend to break easily. Good luck.....

Your check engine light it probably for a coolant system code.

First bleed the system like said above. Are the coolant hoses coming rock hard before the engine reached the normal temps ?? check oil for milk shake and coolant reserve.