Under steering wheel up to the right left corner

I was asked where my fuse box was I wrote wrong place so I said its up under steering wheel to the left up in corner kinda OK I have been told I might have blown head gasket but when asked if the smoke ftom muffler is sweet it's not it's like a burning alil like gas type smell I've also got that I might have a leak without coolant somewhere and it's causing a white smoke my check engine light comes on and off I haven't paid for answer but I've been twice to mechanic that I paid to do oil change etc and both times he said it would be gone now not true it's the same

Testing would kinda sorta be needed , maybe before serious damage is done, and to VERIFY if there really is a problem