HT4100 4.1, 4.5, 4.9 Discussion, '92 4.9 operating temp in Cadillac Engine Technical Discussion; Hello all.
I was just wondering if anyone knows the proper fan cut-in temps for a 1992 Caddy Seville (STS) ...
I was just wondering if anyone knows the proper fan cut-in temps for a 1992 Caddy Seville (STS) with the 4.9. It seems like the temp frequently ventures up into the high 220's before it starts to cool back down. I haven't had an overheat light, but I just wanted to make sure this is normal and that I am not going to fall victim to a faulty fan switch (temp sensor).
Keep in mind that electric fan systems are activated by coolant temp and/or the AC condensor requirements. The AC condensor needs constant airflow over it as the system has little or no thermal inertia...if the AC compressor is running then the fans need to be on ....regardless of engine coolant temp.
So...in the summer when the AC is on the fans run virtually all the time and as a result the engine temp usually stays right on the thermostat setting.
But...in the winter, when the AC compressor is not running, the fans will only come on when the coolant temp gets to 220-225 so it is common to see higher coolant temps in the cooler weather then in the summer..and the coolant temps will vary much more in the winter when the AC is not running since the coolant has to heat up to turn the fans on. In the summer when the fans are running most of the time for the AC demand the extra airflow keeps the engine coolant temp fairly steady.