I FOUND A SOLUTION!!!!
i had the same problem. Sudden appearance of greasy oily hair on the crown area.. And no matter how much i tried washing it and with 4 different types of shampoos, it would not go. i had this once a year ago, i washed it with Johnson's shampoo and it went. However, this time when the greasiness appeared i tried Johnson's shampoo and it dint help. I put egg white on my hair and some of the greasiness went and some still remained. then i decided to try one last thing and then give up. I used henna mixed with beetroot juice and black tea. I used to use this earlier to color my hair. i thought i could help this time because henna dries your hair. I put it on, left it for 4-5 hours. washed it with water alone and no shampoo. After i dried my hair with fingers crossed, to my surprise the grease was completely gone! My hair was entirely clean and soft and shiny as usual! I dint want to shampoo my hair the next day out of fear. So, 2 days later i shampooed it with Johnson's shampoo and did not use any conditioner. My hair is still clean and clear. I am so thankful that the problem went away. I still dnt know wat caused it. Although i think it could be over sweating that might have caused the scalp to become oily since I've been livin in a very hot country for a month with temperatures that go upto 44 degree Celsius. Anyway, it is just an assumption. i understand what you all must be going through because i felt the same for 2 weeks. So, when i found my solution, i thought i must tell you all to try. all the best and I hope it helps everyone!
Mine is greasy and gross too. Its normally oily but I can go with washing it every other day. Not now though it gets too gross! This sounds weird but I use cheap shampoo because its got more cleansers in it and it makes my hair drier lol I still use conditioner but never on the roots. It seems to be helping a bit but I still need to wash every day. Blech
Don't mind my spelling...I'm a bit tired at the moment lol!