A few random comments/suggestions;
If you are running say a 20 psi radiator cap that will raise the boiling point to around 120 degrees, so there's headroom.
I'd wire in an override switch so you can turn the fans on anytime you want.
Oil generally heats up faster than water and doesn't fluctuate as much in temperature, so an oil/water heat exchanger acts as a dampener.
I recall a test on NASCAR engine where it produced it's best power at 85 degrees, we find similar, one of the reasons why we run E85.
Regular leak down tests (both wet and dry) are must on turbo engines, catch problems early before they get big.
Do they have a PCV valve, if so try cleaning it, a quick soak in petrol does the trick.
Cheers
Gary