I run a 185F thermo and rarely get up to 200 in traffic if I'm just cruising. Although, I do have the factory HD cooling.
Assuming the water pump has been replaced: - Impeller to intermediate plate clearance may be too large - WP Plate is corroded and not sealing - WP internal seals not sealing
As on most cars, a high water to coolant ratio may cause an issue too.
