Guys, they ultimate solution appears to be to run the cooler with a thermostat. That way you can make sure your
oil is up to operating temperature at all times, as the thermostat won't direct the
oil flow to the cooler unless it is, and still have the benefit of the increased cooling provided by the
oil cooler when it would be beneficial. I can assure you that I have seen coolant temperatures that are higher than I like to see during slow stop-and-go driving in the summer heat down here in the Houston, TX area and I think an oil cooler would have helped to some degree (but, as there's no fan to force air through the oil cooler, does it provide much in the way of cooling in all that stop-and-go driving?).
Necessary? Probably not in all except the most extreme environments, or usage, but beneficial? Probably somewhat at least and most likely more helpful once under way and getting some airflow through it.
Good to know that high oil temps can be OK....whereas high coolant temps cannot. Thanks for that bit of info!
Cheers!
Doug