Loud Noise At Cold Warm Up

Hey again. I Have a 1988 BMW 535i and here in north carolina it got down to 28 degrees last night so I decided to wake up around 730 this morning to see how my car does starting up in the cold. When I started the car the engine was almost 2 to 3 times louder then it normaly is. And my break lining light was on.I dont know if either of the two have anything to do with each other just figured I would let you know. My back windsheild defrost wouldnt work either. When the car warmed up it when back to normal loudness the break lining light went off and my back windshield defrost worked again. Is there something in my enigne that helps it warm up on cold days (not trying to be funning but everything on this car seams to have the "heated" feature on it). The car wasnt vibrating any different then it normaly does it was just really loud.I thought it was my belts so I poped the hood and it was comming from the engine. Any thoughts of what it could be?