Frothy coolant/thermostat

[James_Audi]

I am due to have my thermostat changed this weekend and I have recently seen that my coolant is all frothy?

I do short journeys (6 mile to work and back) however there is no white mayo type substance on the underside of the oil cap. However I do have a slight oil leak.

Car drives normally (apart from slight lack of power which I presume is the thermostat affecting fueling/boosting.

I have read a lot about head gasket issues relating to this and any help would be welcomed.

Thank you.

 

[James_Audi]

I have been told there is a quick and easy check that can be done to see if it is gases escaping into the water reservoir? Has anybody experienced this? Other bits I have searched make reference to the head gasket more than this.