Use whatever size quart the car manufacturer specifies.
One Imperial quart is about 1137mL
1 Imperial quart = 40 Imperial ounces 1 Imperial quart = 38.34 US ounces (approx.)
1 US quart = 2 US pints 1 Imperial quart = 2 Imperial pints
1 Imperial quart = 40 Imperial fluid ounces
1 Imperial quart = 40 Imperial fluid ounces
1 US liquid quart = 2 US liquid pint; 1 Imperial quart = 2 Imperial pint but US liquid quart/pint isn't equal to Imperial quart/pint.
32 ounces in a quart
1 Imperial quart = 40 Imperial fluid ounces
2 pints in Imperial qt.
In US measure: 1 quart = 4 cups and 1 cup = 0.25 quart. There are 32 US fluid ounces (2 pints or 4 cups) in 1 US quart (946.4 ml). There are 40 Imperial fluid ounces (2 pints) in 1 Imperial quart (1,136 ml). Note that there is no 'cup' in the Imperial system, it is best to use pints or half pints,
A U.S. quart is a tiny bit smaller. 1 US gallon = 3.785 litres so 1 quart = .964 litres. 1 Imperial gallon (British) is 4.54 litres so an Imperial quart is a little bigger than a litre. 1 Imperial quart = 1.135 litres.
An Imperial quart is a measure of volume equal to about 1.2 US quarts.