Radiator cap

[Phil Waterman]

Hi Gilles

I've got a 180F thermostat in my C60S with the 261 cubic inch engine and it has trouble getting up to operating temp takes a good hour on the road to get the oil up 180F, if anything it is over cooled.

I've run all three engines 216, 235, 261 in the trucks and on the test stand, and if the rest of the cooling system, radiator, fan, and water pump are working correctly and the cooling system is clean, think you may discover that without the thermostat the engine will not get up to temperature long enough to keep the condensation in the crankcase and oil evaporated. Take a look at the photo below which is of the side valve gallery of the 261 with a clear cover, the fog is water vapor which dissipates once the engine is fully warm.

I've done flow and temperature test on all three engines with and without thermostat and all three of my trucks have thermostats.

What is the average outside temperature for most of your planned driving? Which fan and pulley sets are you using?

The only reason I don't run a low pressure radiator cap is to protect the radiator which wasn't designed for it and as look as the engine doesn't boil I don't feel I need the raised boiling protection.

Cheers Phil