'97 Civic HX, 5-spsd.
My ScanGauge shows coolant temps between 177 and 181 deg. F.
My Haynes manual says t'stat thermostat rating is 195 deg. F.
Should my coolant temps be more like 195 or 200 deg. F instead of 177-181?

New t'stat was installed about 6 weeks ago, the shop said they got the t'stat from Honda.
Should I replace it AGAIN with another?

 

I'd rather be cooler than hotter.

That may be so it can operate in extremes like Arizona, or here in Texas.

Wait, it opens and circulates right?

 

Yes, the t'stat is functioning. Temp stays very even, just goes up and down a few degrees if I do a long downgrade or upgrade or any other major lengthy changes in engine load. You can't see it on the dash gauge, just on the ScanGauge because that's digital and reads the computer's output.

What is the water temp supposed to be on these cars?

 

For comparison, my ScanGauge reads about 186 fahrenheit and sometimes less (177?) on my car. O'Reilly sourced ECT sensor w/ AutoZone thermostat. This is in the Dallas, Texas area, primarily interstate, on a 1996 Civic (254,000+ miles, D16Y8, stock radiator, 5spd swap).

I've never had issues of it. I think we're well in range, we could even be in the margin of error, there's no telling how accurate the ECT is anyway.

I occasionally get hits up to 190, but it cools down soon enough.

Edit: Also some fun trivia: While unplugged, -40 F (that's how I knew my ECT blew ) and when wires cross, 418 F (I shat myself and killed the ignition).

 

Depends where the temp sensor position is in relation to the thermostat and the accuracy of both.
I wouldn't worry about a few degrees difference.

 

This is true as well. ECT is just about a foot from the thermostat, the water passing by it could have already done its job and started cooling off (or hasn't touched engine yet, I'm not sure which direction these things flow ).
(offtopic: also, our cars are held together by 10mm headed bolts.)