454 Running Hot

turbojimmy wrote:

Gjac wrote:
The OEM fan clutch moves a lot of air at any speed. It is controlled by air temperature not engine temperature. If you are going 60 mpg on a flat with little load it should not come on, once you hit a hill for any length of time your speeds will drop your temps will rise and it should then come on. When the coil spring sees about 160 degrees it will lock up, when the temps drop it will free wheel. You might be thinking about the electric fan on the front of the radiator. That does not seem to make too much difference at 60 + mph but does lower the engine temps at idle and lower speeds. Some of the older fan clutches have several notches that can adjust what temperature they come on. Mine is a 1996 and only has one notch. You can also clean the spring with a tooth brush and carb cleaner to remove dirt and any grease build up which will insulate the spring and cause it to come on at a higher temperature.

Thanks for the info. I don't think mine is coming on at higher speeds. Nor does it seem totally dependent on temperature. For example, when I left the campsite on Monday it was roaring when I left the spot, but I had just started it up. Anything just above idle I don't hear it at all. Like I said, the only time I heard it above idle was when it was really hot after that hill climb by my house. Which again begs the question - am I over reacting to the stock temp gauge? Maybe the fan is working like it should and it really isn't that hot?

Jimmy, the fan clutch is suppose to come on when the eng is first started after a minute or so it will disengage and quiet down. If your cooling system is working properly the fan clutch should not come on unless you are climbing a long steep hill or shorter hills on a very hot day. You can check the fan a number of ways. The easiest way is to spin it if it rotates more than several revolutions, if you see silicone leaking out, or if it has excessive play then I would think about replacing it. The fact that it comes on when you start the eng, it comes on after a hot hill climb and your temps recover quickly sounds like it is working the way it should. Like I said in my first post anyone can change parts based on age (we have all done it) but it takes a little more thought to figure out what is wrong first if anything. Do the thermostat and radiator testing first before you start throwing parts at it, it will be cheaper for you in the long run. I would suspect a 30 year old radiator and test that first.