When i turn the defrost on the windshield there is at times a bad smell, like burning rubber or oil. It only happens once and a while. what can I check to see what is causing the smell. It worries me.

 

have you changed your cabin air filter?

 

Is there any fog or condensation on the windshield. Your heater core could be leaking.

 

i have the same problem.
how did you make out?

 

The smell of burning oil is probably burning oil. A leaky valve cover gasket, can adjuster seal or cam seal will allow oil to drip on the exhaust manifold causing the smell. You only get it once in a while because it is a small leak and you get it when you turn on the defrost due to the volume of air being moved and the fact that the air is being moved up by your nose instead of at your feet.

But, make sure to change that cabin filter, as well!

Bob