[cycleguy55]

210°F is nothing - mine has a 180°F thermostat (starts to open at 180°F) and typically runs 180°-210°F on the open highway and 190°-220°F in traffic. It's worth noting I'm running a high-flow thermostat and the plate has two 3/16" / 5mm holes drilled in it to ensure full purging of air. Those additional holes do cause it to take a bit longer to warm up when ambient temperatures are cool - like this morning when it was 3°C on the run in to breakfast. Yikes.

BTW, the car hit 250°F in traffic a couple of weeks ago when the cooling system fan relay quit working and, while it spit a bit of coolant it did not 'boil over' - the result of a pressurized system running 60% ethylene glycol. The manual override switch on the dash made no difference as it just activates the relay. The single relay (from a C4 Corvette) has now been replaced with a pair of 40 amp relays wired in parallel - they share the load and either one alone is sufficient to handle the load, should one fail though, of course, that will never happen now that I have redundancy!