Mayo on the oil cap is common on them - more usually it's the timing cover gasket behind the water pump that causes excess emulsion, people run them until it gets worse, then it overheats, then the head warps - so it always gets diagnosed as HG failure when that is a result rather than the original cause.
Photo? Mileage / Year? (if possible please)
Photo? Mileage / Year? (if possible please)