MG Car Club of South Australia
MGC NEWS
MGC conversations with Richard Mixture, August 2018
cooled making the cooling system more
efficient.
MGC Thermostats
H
ello, it’s Richard here again to talk
about a hot head or really it’s
about keeping a cool head. If you re-
member that nice young MGC Co-
ordinator had a hot head and fixed it by
replacing the viscous fan clutch which
he had first modified way back in 2003.
The fan now keeps the ‘C’ cool but the
thermostat was a 71° item which is too
cool and needs to be replaced with a
standard 82° thermostat.
A modern by-pass thermostat can be
fitted an MGC but the foot valve is too
far away from the by-pass hole to work
efficiently. It needs to reach a further
3mm closer to the hole. To achieve this
extra length a washer/washers can be
soldered to the foot of the thermostat.
Thermostats often have a jiggle pin in
the flange that allows trapped air to be
released. The jiggle pin should be ro-
tated so that it is at the highest point in
order to release any trapped air. This
rotation is not important in the MGC as
the thermostat is located in a horizontal
position in the head. Cars that do not
have a jiggle pin in the thermostat usu-
ally have a bleed notch or some other
method to release trapped air.
So what is a thermostat, just in case
you’re wondering? It is a valve that
regulates the flow of coolant from the
engine to the radiator. When the ther-
mostat is closed (in a cold