stock gauges reading high / incorrect

tony starr

tony starr

Senior Member
Hello gents, what would be the cause of the standard Ford gauges reading high? Bad sender units, incorrect wiring somewhere or they just need to be re-calibrated? For me, it's the temp gauge on a fairly stock 6 volt '41.

Thanks.
 
Ford original gauges (king Seeley) are very durable and seldom fail unless killed by shorts or overvoltage. I would take a guess that you have an aftermarket sender unit and it will never be accurate. Did you test the gauge and sender off the car with a thermometer and pan of water on the stove?
Just an opinion
 
When the car is not running the dash temperature gauge reads all the way to the right or HOT. When the engine starts the gauge starts to move to the left or Cold. For 41 the engine has two sending units if the two terminal unit open circuit the gauge will always read HOT, if the two terminal sender is shorted (normal condition) and the single terminal unit opens circuit, the gauge again reads hot, if one of the wires to the gauge or the senders brakes or open circuit the gauge will read hot again. If the gauge moves correctly (Hot to COLD) just reads high all the time, it is usually the fault of the single terminal sending unit.
 
Make sure the sender(s) are grounded. If you used any Teflon tape or sealers around the threads the sender may not be properly grounded.
 
I assume you have stock Ford temp gauges that are electric and its probably the two-sender unit temp gauge system. In my experience the double-wire terminal sender unit on the driver's side head seems to malfunction more frequently. On my '47 I by-passed the two-terminal sender unit and just use the one-terminal sender on the passenger side.

To be considered .... the one-terminal sender unit is located in the passenger-side engine head where the hot water heater circuit connected to it. If so, that side of the engine takes a little longer to heat up because it technically contains more coolant. Its also said among some Ford guys that the passenger side of the engine runs hotter than the driver's side due to slight differences in the block design.

As noted, these gauges usually don't need re-calibration unless damaged. There are gauge re-builders that do this. They can be checked and adjusted but one needs an accurate mechanical gauge in order to do it. I have dis-mounted Ford gauges inside the car and fine-tuned them to be similar to a mechanical gauge I have (i.e. oil pressure).

In the big picture, stock Ford gauges were generally intended to show a good approximation of conditions.
 
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