Creamy white emulsion under oil filler cap? Water?

Gidday all - I have a (don't laugh) 1973 Land Rover series 3 with a 1960's holden 186 motor, which is a 3 litre. Its probably done hundreds of thousands of miles. When I open the oil filler to top up the oil, this ugly looking creamy caramel mess is under the cap. It wipes off easily, and I can't detect any specific smell from the goop. It feels greasy between the fingers.

I know the cap isn't quite the right one for the motor - it should be a dome-shaped breather. Searching the web suggests its a gasket leak, or a cracked head or a cracked block. But the motor runs alright... a lot less powerful than a modern one, but fast enough. Should I take the head off ? I'm a mechanical noob but in the six months owning this car I have done a diff (twice) a half shaft, and a starter motor as well as points/plugs/etc. Unf. money is tight so I can't just take it to a garage :(

a 5 gas test with a compression should verify if u have a blown head gasket or head/block structural cracks ..it'll cost u less than $100 from a shop...if ur time worth less than a $100 to pull heads out and take it to machine shop to chk cracks ..then i have a better idea...get a 2nd job pay the shop $ 100 to find out and u'll still have more change left than doing it urself.
another possiblity is leaks manifold,or transmission cooler @ the radiator leaks ....if the car is running find ...u might have a good chance that it is not a blown head gasket,crack blocks,heads...etc....

by the way ..i heard of so many times about crack blocks ...i haven't seen 1 for the last 10 yrs in auto reapir business.....maybe i am just lucky huh?

good luck

I have yet to see a cracked block either Kin.

Letting an oil change go to long can give the cap that look, especially up here in the northern winter months.

LEt it set over night. SLOWLY, remove the oil drain plug and catch a 1/4 to a 1/2 quart of oil in a clear container. The water/coolant will settle to the bottom of the pan and will be evident as to how bad it may be.

If nothing obvious, drain the rest of the oil. leave the plug out and pressure test the cooling system. Again have a clear container under the oil drain plug hole to catch any possible coolant. LEave the system under pressure overnight.

Thanks for the thoughts guys. Seems that older engines are suseptable to this, more so when its cold (winter here now) and more so when there are lots of short runs where the engine never gets very warm. Also, the correct breather cap is not fitted... the one in the photos should look more like this one

So this will help a lot. Yay for vintage gear -wink-