Can you help me please Oil prob ?

There are two types of color you may be asking about. One is a color coding for the caps, vents, and valves for various substances, and another is the coloring of the substance themselves.

224.14 Color coding of fill ports.

(a) The owner or operator of a retail establishment selling petroleum products from underground storage tanks shall permanently mark all fill ports to identify the products inside. These markings shall be consistent with the symbol code of the American Petroleum Institute which follows.

(b) The colors to be used are:

(1) High leaded gasoline red

(2) Middle leaded gasoline blue

(3) Lower leaded gasoline white

(4) Higher unleaded gasoline red w/white cross

(5) Middle unleaded gasoline blue w/white cross

(6) Lower unleaded gasoline white w/black cross

(7) Vapor recovery orange

(8) Diesel yellow

(9) #1 fuel oil purple w/yellow bar

(10) #2 fuel oil green

(11) Kerosene brown

http://www.agmkt.state.ny.us/WM/RegPart224.pdf

As for the colors of the actual products, those can vary depending upon the manufacturer. The actual fuels themselves are essentially colorless, or may have a slight yellow to tan appearance. Sometimes dyes are added.