Head gasket

I only seem to have white smoke on morning, after the engine warms up there is no smoke. Another thing that I have noticed is that if I have the car sitting in neutral and give a few revs black powder comes out of the exhaust. The milky substance is only on the oil cap and not on the dipstick. How can coolant be mixing with the oil if the coolant reservoir levels are not dropping at all?

I will be taking the car to my mechanic after Christmas so I will post the outcome then. When I drive the car for a long period and check the oil cap after the butter/mayo like substance is gone. One thing I forgot to mention before is when the engine is on and car is in neutral you can smell the sweet smell from the exhaust inside the car. I have also noticed on the dipstick above the oil level there is a slight amount of the whie/yellow creamy substance. The oil is still the same colour, not brown. Also the check engine light is not on. Thanks for the replies. I will reply after the new year. Happy Holidays

Yea I thought as much. I am hoping it won't be very costly. I didn't pay much for the car to begin but there was other things I wanted to do. Once I get it to the mechanic I will post a reply and let you guys know. Thanks for the replies and input.