Coolant temp

My sw gauge is reading like 220 to 230 degrees, my scan master is reading 175. Is this basically the sensor for the gauge or should I look elsewhere
I think that I would trust the Scanmaster over an after-market gauge.

Find a thermometer & place it into the radiator filler. Let the car run with the radiator cap removed & see which of the 3 readings match the closest.
I also bet the SM is right. Are your fans wired stock with low / high? If so and fan isnt high, your aftermarket gauge is wrong. ASSuming you dont have 2 problems

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