If you think about it, cooling systems have a thermostat that restricts flow into the radiator when required. This keeps the engine at a constant and optimum operating temperature. Engine oil temperature also requires an optimum temp. An oil-to-air oil cooler may vary operating temperatures greatly depending on atmospheric conditions.
Having the oil temp effectively controlled by the coolant temp would keep the operating temp more constant. With the specialised oil requirements of Formula 1 engine (even back in 1979) this would greatly increase engine life.
I'm sure Cosworth would have given customers the optimum oil temperatures they required the DFV to run at for longest life and best performance.
PJGD quote: "The optimum operating temperature for both coolant and oil are essentially the same so why not use a single radiator and a single temperature controlling thermostat."
This is generally correct. But I have predominately been involved in open wheeler racing and have often seen cars with "hot zones" and "cool zones" within the engine bay. Effectively keeping lower engine area (crankcase, dry sump and ancillaries) running at a hotter temp then the "cool zone" (head, intakes, coolant pipes etc).
These zones would be in the form of tightly fitting aluminium or carbon fibre panels that would not allow leakage ie: hot air into the cool zone or cool air into the hot zone.
It is a fascinating part of modern race car design.
Edited by Porsche718, 30 January 2023 - 05:25.