yeah you will, only a bit more, just check the dip stick
chuck in around 4.5L to start with
if its got a thermostatic plate you'll have to get it hot, then turn off the engine and top up to the max mark
sorry to go of course, but how much was the oil cooler? and what are they like to fit?
this.you should fill the oil cooler with oil, and the pipe work.
As when the thermostat opens there will be nothing in the pipes/cooler.
This could lead to the engine being starved of oil.... not ideal.
Is there anything wrong with mounting the oil cooler with the pipes underneath rather than on top?