Not long ago I was driving and my temps went above 200. It came back down and didn't do it again for a few drives later. I replaced the rad cap, OEM thermostat. After that it was fine briefly and than I went to use the heat and there was none and as soon as I moved the seeting to heat the temps spiked again. I got the front end real high and burped a ton of air out. Seems ok but now its running 174-192. Prior to any of this it was 172-178. Never went into 180. Fans are working. Any thoughts on why its reaching 192?

 

The engine coolant system is designed to keep the engine at optimum operating temperature. Not just keep it cool. Gasoline engines run most efficiently right about 200°F. 172°-178° is definitely too cold. 192°that you're seeing is in the range it should be. 210° or 220°F is nothing to get concerned about.

Standard Thermostat
Starts opening: 169-176F (76-80C)
Fully Open: 194F (90C)

I data captured and graphed my Expedition towing a trailer across the PA Turnpike thru the mountains. Darn near a flat line just below 200°F right where an effective cooling system should maintain it. Haven't done the S2000 but I'd not want it running 170° or 180°F.

-- Chuck

 

Interesting, for the 7 years ive had my EMS serial gauge in there it ran under 180 so Im not sure about that

 

Ap1 cooling fans don't even kick on until almost 210°. Not sure what temps you guys were reading. Possibly different on ap2. It will doubt it.

 

I don't think that's accurate. My fans are 179