VW Golf 1.6se 1998, S Reg

Hi, not sure if this will get back to 98 DAK, who kindly responded to a previous query that i had with my 1998 Golf with emulsion in the oil filler cap. The yellow, white stuff is not really foamy, more of a sticky residue and seems to be on the filler cap itself and around the top part of the oil tank. I have kept an eye on the water coolant within the header tank, i can see no visible signs of any leaks, and i do not seem to have lost any coolant, the temperature guage does not exceed the normal level and does not over heat. I was told that as the filler cap has a little play, this may cause moisture to arise. I am not really clued up on engines, but know that it is bugging me. Will the gunk cause damage to the engine or affect the performance. If you could shed any further light on the problem or any further tips on sorting i would be very thankful. Thanks again.

Even with the play in the filler cap, the residue should not be yellowish. This concerns me.You could... wipe away the residue and replace the cap Some coolant leaks are not visible, due to the fact that the leak is so minimal that you do not notice a coolant loss. A leaking head gasket can have the smallest amount of seepage. as far a damage being caused if it is a leak, not really. Just check coolant every week or so, and I would replace the cap