I have a 99 540 with 70,000 miles. The car has been very well taken care of. After driving, a hot rubber smell comes from the engine compartment. It does not smell like hot oil but rather hot rubber. I noticed that the power steering fluid reserve had leaked somewhat. Could that be causing the smell?
Hot rubber smell coming from engine. on 1999 BMW 540i
What your smelling is probably your belt. Have it inspected right away or going to leave you stranded. Like answer #1 something binding up belt.
1 more answer
one of your pulleys is freezing up