Front Engine Oil Temperature?

[Mich3773]

During a recent front propeller overhaul (mandatory every 10 years in Canada) excessive corrosion was found inside the front propeller. Looking back over engine monitor data, I found that the front engine oil temperature is rarely above 130 F, even during the summer. I assume water vapour condensing and accumulating in the oil is the source of the corrosion. There's never been any evidence of water in the oil on the dipstick or in oil samples. CHTs and EGTs are within normal ranges. I'm thinking the front engine oil cooler is over-sized, there's too much airflow through it, and a plate needs to be installed on the outlet to reduce the air flow and increase the oil temperature.

What range of front engine oil temperatures do you see? Your thoughts?