I'm with LarryBible here!
This is all to familiar to me. You must not have seen my threads around here the past two weeks, lol.
I thought this was my resolution as well. Then I later noticed the car getting warmer and warmer. To make a long story short, I get to go and pick-up my car tomorrow and the head gasket will be fixed, lol.
I'm thinking this is why Larry asked is there any coolant in the oil, or vice versa. I know it feels good to get a "cheap fix" but your car is worth far more down the line, than your emotions are right now in feeling good that you saved some cash.
Have your engine checked out on Monday. Or if you do your own work, put your hood up, turn your heat on as high as possible (full blast) and while sitting in park, gas your car for around 5 minutes. I mean, give it some gas. A loose, or bad expansion tank lid shouldn't cause smelling coolant. Engines are funny, you won't smell the coolant all the time so I'd not get too at ease about it right now. After you gas your car, HARD, for 5-10 minutes, get under the hood and see is any coolant in the oil, or vice versa. Your coolant shouldn't even be jumping-up to the point where your tank lid would even contribute in leaking. That tells me there's some built-up pressure in there and that there's likely a leak in the pistons, either inside or outside.
I'm not trying to scare you, but this is too familiar as I too thought I had a quick, less expensive fix.