purging

It takes care of itself.

Contrary to common expectation, the Oil Thermostat is OPEN when COLD allowing the majority, but not all, of the oil to bypass the Oil Cooler.
When the Oil reaches temperature, the thermostat CLOSES which stops the oil from bypassing the Cooler.
The Oil cooler is not an All or Nothing arraingement; more like 30% Cold, 100% Hot.

Purging the Oil line will purge the Cooler at the same time.

Watch the Oil pressure closely on the first start.
Oil pressure should be >20psi withing 5 seconds (Usually immediately).
It might fluxuate slightly for the next 5-10 seconds and then becone steady.
After 30 seconds every inch of hose has been refilled twice and and the cooler at least once and you can quit worrying.