Low temperature thermostat

[Starter986]

Originally Posted by JFP in PA

Here's were your thought train goes off the rails:

When the LTT engine reaches its opening temperature, it begins to open partially and waits to see what the circulating coolant temp is, it does not suddenly pop open or slam closed, it moves in steps controlled by the coolant temps it sees. If it begins to drop (say the outside air temp is 50 F), the stat closes partially to bring it back up to its design temp. This is the throttling action. Eventually the engine will reach what is called "steady state" or some level where it plateaus (lets say you are driving at 40 MPH on an open road on a pleasant spring day). The OEM stat will go steady state on a 68 F outside temp day at around 210-220 F. The LTT under the same conditions will go stead state around 170-175 F.

One of the biggest problems in seeing this is the poor quality of the dash temperature displays in these cars; they are both woefully inaccurate (coolant is actually at 215 F while the display says around 180) and non linear (the gauge sweep is not in even increments). As such, they are little more than idiot lights that move. On vehicles with after market temp gauges, the difference is obvious, with the OEM display, the needle movement difference is tiny, leading people to reach the same conclusion you have: There is no difference, which is not correct.

On fully instrumented engines, we see 170-180 F steady state readings on the coolant, and even more important, drops of 25-35 F (or more) in the oil temps with just the change of the stat. That is huge.

We like the MotoRad aftermarket stat, which is what LN sells as their product; well made and consistent.

I've returned to the rails. Thank you for that revealing narrative!