Hello, I have two questions about our thermostats:

I replaced the thermostat on my 1997 Acura CL 3.0 less than a year ago and it's always bugged me that the temperature gauge seems to stay a little lower than it used it. The needle is about 1/4" below the halfway mark (but well above the quarter marking).

I installed a Stant thermostat, # 14127. It's rated at 170 degrees. I've Googled for a while, but I can't find what the stock thermostat temperature is supposed to be. I know from the previous thermostat failure that when the engine doesn't warm up to where it should be, it has trouble shifting especially to 4th gear.

So,

1) Does anyone know the exact stock thermostat temperature is supposed to be for the CL 3.0? And is it the same for any J30A1 motor, like on the 98-02 V6 Accords?

2) Is there any benefit to having a thermostat rated at either 170, 172, or 180 degrees?

I'm asking because this info will help me decide whether to replace it again or not. I'm in the middle of a lot of engine work over this Summer, and I can always clean and save the Stant one as a backup.

 

The shifting problems are not related to the temperature of the engine. The Transmissions in these cars are notoriously bad

 

Thanks 97BlackAckCL, I've heard so many horror stories about these transmissions, though so far it seems like mine's holding up. Hoping to change the ATF fluid before putting the car all back together. I won't attempt unbolting or taking the tranny apart unless the rear main seal goes very bad.

My old thermostat that went bad was a stuck open type, so when it failed, it took long for the engine to warm up. When I was on the highway, I could actually see the temperature gauge go from near halfway down to almost all the way down. At operating temp, when the car was locked in 4th gear at 2000rpm, the car would be going ~54mph. If the temp gauge started going down, it would take a higher rpm to maintain that speed. I don't know what the exact relation is, whether the ECU decides based on temperature readings, or if it's the coolant/oil/ATF temperature or pressure that allows the torque converter to lock.

In any case, do you or anyone else happen to know the stock Honda/Acura thermostat operating temperature?