Frothy Coolant

Hi,
Perhaps someone can confirm my diagnosis, 1986 110 CSW, when I stop the
engine, coolant is ejected out of expansion tank tube. I have noticed
small bubbles in expansion tank and after a mile or so coolant is
'frothy'. There appears to be no oil in coolant, or coolant in oil and
the temperature hasn't gone over normal levels. I'm guessing its the
head gasket just starting to go, does anyone agree, or could it
possibly just be the spring in the expansion tank cap is U/S?. I have
bought a gasket set to replace this weekend, anything to watch out for
in this job, it looks fairly straight forward in the manual...

Smudge

yes, more than likely head gasket i reckon. If there's no oil in it
then it's maybe gone between the cylinder and the water gallery.

Depends what engine it is as to ease of changing. I do alot of work on
outboards and I find that the problem is not changing the gasket itself
but what caused it to go in the first place!

Dave