I have been noticing an intermitent burnt oil smell for some time now. Was constantly looking for slicks under the engine after being parked, and have never seen any brown or black stains in the snow either. Recently while checking for vaccum leaks I noticed little puffs of white smoke rising from between the rear of the motor and the firewall. My mechanic says the rear seal has a slight leak and since my oil level is not dropping abnormally I shouldn't worry about that much as it is kind of a costly repair. I don't think I want to put up with intermitent burnt oil smell inside the car all summer so may fix it sooner than later.

Any thoughts?