My Autometer temperature gauge behaves the same way. It doesn't really surprise me that it runs in that cycle.
You would have to have a pretty serious control system to keep your temperature real constant. You didn't mention what temperature you have for your thermostat. That would affect the cycling as well. If you think about how heat is regulated in a house, the thermostat reads too cold and that causes the heat to turn on. Even if the flow of heat stops when the thermostat gets up to temperature, you still end up overshooting that number by a bit. It's effectively a sine wave.
As for the oil pressure, you can put a tee fitting where the factory oil pressure switch threads in just above the oil filter. That way you don't have a dead dash gauge.
You would have to have a pretty serious control system to keep your temperature real constant. You didn't mention what temperature you have for your thermostat. That would affect the cycling as well. If you think about how heat is regulated in a house, the thermostat reads too cold and that causes the heat to turn on. Even if the flow of heat stops when the thermostat gets up to temperature, you still end up overshooting that number by a bit. It's effectively a sine wave.
As for the oil pressure, you can put a tee fitting where the factory oil pressure switch threads in just above the oil filter. That way you don't have a dead dash gauge.
It sounds like the fan thresholds were tuned kinda strange. You dont want the fan to turn off at the stat rating, as the fan will effectively seldom shut off (given the error in stat opening rates).
I agree that if this occurs while you're stationary or going very slow, it's normal. The fan is the only real means of pulling air across the coil.
But if this occurs at speed, there's an issue.
And regarding the fluctuations, a Dc Controller is an example of how to get around the antiquated 'overshooting' that Matt mentioned. I have mine set at 187* F (balanced t-stat opens fully by 183*F) and it ramps the fan up as much or as little as needed to keep the car at 187*F (the limit being if the fan cant keep up. I see this a little bit when ambient temps are around 115*F+).
Good luck.
I agree that if this occurs while you're stationary or going very slow, it's normal. The fan is the only real means of pulling air across the coil.
But if this occurs at speed, there's an issue.
And regarding the fluctuations, a Dc Controller is an example of how to get around the antiquated 'overshooting' that Matt mentioned. I have mine set at 187* F (balanced t-stat opens fully by 183*F) and it ramps the fan up as much or as little as needed to keep the car at 187*F (the limit being if the fan cant keep up. I see this a little bit when ambient temps are around 115*F+).
Good luck.