Often a knock when cold is caused by piston slap, which is pistons rocking in the cylinders until they expand in size when the engine warms up.
This is where you swear by everything you consider holy that you will NEVER EVER buy another French car.
No, warn engine parts will cause loss of oil pressure as the engine warms up, due to expansion betweeen moving parts. Hot oil is thinner.
NO, it will not damage the vehicle engine by turning the heater ON before the engine has warmed up fully.
False
You are burning coolant. What vehicle? did you do a compression test?
If its coming from your engine, you may need a valve adjustment..
Does it quit shaking when it warms up? What engine and year of Aerostar?
Then you need to have code checked, you can diagnose from there.
The preheater warms up the engine so it will start easier and in freezing weather will help to avoid freezing of the coolant.
this is caused from piston to cyl wall clearance when engine warms up the pistons exspand and the noise is less. DON'T WORRY ABOUT IT
It cuts off the engine while you start it up.