Possible reasons for a creamy oil cap ?

[joelk]

Hi there,

I'm about to buy a 456 - but one I have seen had a creamy coffee like residue on the underside of the oil cap.

I heard this normally means there's a problem with the head gasget. Or - are there other possible explainations for this? (seeing it's a V12). The sales people suggested it was due to condensation build up as it had often been used for only very short journeys.

Many thanks...