2001 C5 operating temperature
1/4 mile/AutoX
Joined: Jun 2014
Posts: 11,439
Likes: 2,184
From: Buffalo Texas
This is simply wrong. No if's and's or but's. Wrong.
The thermostat begins opening at it's rated temperature and then opens fully from there as the coolant temperature increases another 10* to 20*. The thermostat isn't just open or closed.
Given enough radiator and fan, the engine will ALWAYS run just above the thermostat rated temperature. The thermostat will partially open and regulate the radiator flow to maintain the coolant temperature. My C5 with the stock 193* thermostat runs just a little over 193* at the highway speeds I normally drive until I slow way down or stop and there is no longer enough airflow. At that point, the coolant rises until the fans come on and once again provide enough airflow. My 65 Impala with electric fans does the same thing.
The fact the OP's car is running at a lower temperature after the thermostat was changed to a lower temperature rated thermostat also proves the thermostat regulates the lower end of the coolant temperature.
There wouldn't be thermostats with different temperature ratings sold if they didn't change the operating temperature of the engine.
The thermostat begins opening at it's rated temperature and then opens fully from there as the coolant temperature increases another 10* to 20*. The thermostat isn't just open or closed.
Given enough radiator and fan, the engine will ALWAYS run just above the thermostat rated temperature. The thermostat will partially open and regulate the radiator flow to maintain the coolant temperature. My C5 with the stock 193* thermostat runs just a little over 193* at the highway speeds I normally drive until I slow way down or stop and there is no longer enough airflow. At that point, the coolant rises until the fans come on and once again provide enough airflow. My 65 Impala with electric fans does the same thing.
The fact the OP's car is running at a lower temperature after the thermostat was changed to a lower temperature rated thermostat also proves the thermostat regulates the lower end of the coolant temperature.
There wouldn't be thermostats with different temperature ratings sold if they didn't change the operating temperature of the engine.
Safety Car
Joined: Jan 2012
Posts: 3,956
Likes: 520
From: Da U.P.
Any insight into why the oil being that hot helps with engine longevity? What exactly does it protect that say 195* oil can't protect?
The OLM counts 50*C oil the same as 100*C oil, so GM doesn't seem to believe the oil needs to get that hot to have a full life.
My C5 on the 25 minute drive to work barely gets the oil to 190*F. Sometimes it's even cooler when I park it. On much longer highway drives the oil temperature typically won't go above 200*F either. And that's with the stock thermostat.
The OLM counts 50*C oil the same as 100*C oil, so GM doesn't seem to believe the oil needs to get that hot to have a full life.
My C5 on the 25 minute drive to work barely gets the oil to 190*F. Sometimes it's even cooler when I park it. On much longer highway drives the oil temperature typically won't go above 200*F either. And that's with the stock thermostat.
