Rover V8 3.9i Coolant Return from Plenum on Hunter

[greyV8pete]

I had often wondered about the way Marlin had routed my return coolant pipe from the plenum hot-spot back into the radiator top hose, as this effectively by-passes the engine thermostat and constantly bleeds hot coolant into the radiator. I have now changed this so that the pipe goes across the engine and into a Tee in the heater return line. This allows much quicker engine warm up ( about 2 miles instead of about 10 miles on a cold day). It also means that the rad stays cold until the thermostat opens, so temperature control is more instantaneous. This is the system that is used on the MGB V8, which uses the same engine. I believe that some of the later Hunters were also plumbed this way. Worth checking, if you have the same engine, as re-routing the return pipe is a definite improvement. Peter.

ORIGINAL RETURN PIPE - (In front of oil filler)

ORIGINAL RETURN PIPE.jpg

OLD RETURN BLANKED OFF

OLD RETURN BLANKED OFF.jpg

NEW RETURN TEE

NEW RETURN TEE.jpg