My bad guys, i've only just read the OP properly - I only responded to the title and the first reply
The 'mayo' under the dipstick is from condensation, nothing to do with engine coolant and is totally unrelated. If you are losing coolant then you have a leak (or are burning it). The latter normally comes with other symptoms, such as mixing of oil and water one way or t'other, pressure in the header tank, exhaust gas in coolant circuit etc.
You more than likely have a leak. As I said, mine leaks a little but its from the water pump (cheap aftermarket part). Mine has a tell tale drip from the bottom of the engine cover nearest the turbo outlet/discharge pipe. It does seem to be a common thing with the waterpump so worth checking