So every time I put the heat on in my car it smells like oil specialy when I put the defrost on n it leaves oil spots on my windshield.Those this mean I'm burning oil can it be my valve cover gaskets or some thing else I'm new to the nissan game some please help me out thank you

 

i no the rear valve cover always leak. they are knwo for that. i have had 2 diff max and they both were leakin. and i work at a shop and have had 8 the same thing. cheap it. wat you could do is purple power everything thats oily and wash it to clean it up and drive it for a wile and just keep an eye on it and see if you see it leaking. you will notice it if you clean it well it will have a moist look to it all if its still leaking.