esa aardvark mentioned oil dilution. There was provision for it on some of the L-1049D's but it was deactivated. I believe the Navy R7V Connies I serviced at Lockheed New York that were modified for use down in the Antarctic had it activated. They also had a combustion heaters in the nacelle for preheating the oil tank.
(think the Connies were El Piasano and Roadrunner)
Problem with oil dilution, as I recall from hearing, not having ever used it, is that the gasoline mixing with the oil loosens sludge throughout the engine. There is a lot of sludge in the oil deposited in such places as the prop dome on Hydromatics and in sludge caches in the crankshafts and other places in some engines. The dilution freed up some of this sludge and it was required you pull the oil screens after use of oil dilution.
I deeply sympathize with anyone pulling sump plugs and oil screens in -40F as it was bad enough at +5F.