Unedited, what more can I say?
"The K-series engine is prone to head gasket failure whatever car it is
installed in. The problem is worst in big, heavy cars like the
Freelander, but it happens in Elises and Sevens as well.
Light, compact and powerful as it might be, the design of this engine
is deeply flawed in several key areas. The design of the seal between
the top of the liners and the head/gasket places too much strain on
the gasket and causes premature failure. Not helped by the metal of
the liners expanding at a different rate to the surrounding block and
head.
The second problem is that the standard of casting on these engines is
crude, and varies dramatically. If you get a bad one it seems to pop
gaskets until you give up and chuck it in a skip. Others are better.
It's pot luck what you get.
The third problem is that the thermostat is placed on the return from
the radiator rather than the outlet. A ludicrous design which relies
on heat soak from the head side of the 'stat to "overcome" the cold
water in the radiator before the thermostat opens. This holds the
thermostat closed for too long, causing head temperatures to rise
excessively. When the thermostat does eventually open, this (too) hot
cylinder head is suddenly subjected to thermal shock from the cold
radiator water hitting it. It's a comically bad design.
The thermostats have also been observed to "bounce" several times
before they open. As soon as the cold water rushes through, it closes
the 'stat again, causing head temperatures to rise again. Repeat two
or three times for each engine warm up cycle. The only surprise of K-
series head gaskets is that they last as long as they do."
