Heat Soak Problems
Your
engine temperature is controlled via the cooling system with interplay between
heat produced, speed of water pump and engine cooling fan all controlled by a thermostat.
When the engine is switched OFF, the cooling system becomes inactive and the
residual heat in the engine from the block, head and exhaust manifold are
transferred to the coolant and other engine components.
If the
head is alloy and the block cast iron, heat soak is a particular problem as
they will expand at different rates, and there is a long term risk of head
warping, gasket damage etc.
As the
graph shows, the typical effect of a conventional cooling system is that over a
long period the coolant is almost at boiling point until natural convection and
radiation eventually bring the engine and coolant system back to ambient.
For an
intelligent cooling system, an electric water pump and electric fan are
controlled by engine temperature irrespective of whether the engine is OFF or
ON. The effects of 'heat soak' are washed away in seconds as the cooling system
continues to do its job whilst the engine is OFF.
To
overcome damaging heat soak in your engine we recommend the combination of the
Davies Craig Thermatic fan, Electric Water Pump (EWP) and a EWP Dual
Controller.