The car is not starting when the engine is very cold, the possible reason is that the engine oil is too thick or is not within the specification recommended by the car manufacturer. Another reason is the battery maybe weak.
Possible Cause why Car will not start when the Engine is Very Cold
Engine Oil is Too Thick
When the car uses engine oil that is too thick which is heavy single weight engine oil, the oil has a tendency to become very thick when the temperature is cold. It becomes so thick that the engine has trouble cranking when trying to start the engine because of the extreme friction cause the thick oil.
Use different engine oil which is multi-weight oil such as 10W-40. This type of engine oil will not thicken when the temperature is very cold which prevent the engine from hard starting.
Weak Battery
When the surrounding is very cold it can cause the battery to become temporarily weak if this happens the engine will not crank fast enough to cause the engine to start.
Replace the battery with a higher Cold Cranking Rating. A battery with a high cold cranking rating has the ability to work in a very cold temperature.
