I've seen a few messages on this topic, but now I have some hard numbers to deal with.
I put a new radiator core in my '69 350/300 along with a 180 deg. thermostat and a new temperature sender. I also installed all new foam seal around the radiator. I got the temp unit, M112B from ZIP with a new pigtail (wire and clip). When driving, the temp guage has been showing between 212 and 225 deg. F consistently, depending on the outside temperature for some time.
Today, I clamped an A/C type thermometer (metal stem with a button dial) on the side of the top radiator hose next to the thermostst housing. The outside air temperature was in the low 70's. I drove the car for over an hour and it showed a steady reading -- did not move. The guage goes from 210 to 250 with only one hash mark in between, so I'm guessing it was reading about 212-215 deg. F.
I stopped the car with the engine running and popped the hood. The thermometer read 172 deg. F. I continued to drive the car and when I stopped and shut it off, the temp guage read about 205-208 deg. F and the thermometer read 175 deg. F.
Temp Guage Thermometer
at idle 212-215 172
stopped 205-208 175
Can anyone tell me if these temperatures make sense and how to correct the guage reading. I've heard you can put a resistor in-line from the temp sender, but how do you know how many ohms???
Thanks,
Jim #33086
I put a new radiator core in my '69 350/300 along with a 180 deg. thermostat and a new temperature sender. I also installed all new foam seal around the radiator. I got the temp unit, M112B from ZIP with a new pigtail (wire and clip). When driving, the temp guage has been showing between 212 and 225 deg. F consistently, depending on the outside temperature for some time.
Today, I clamped an A/C type thermometer (metal stem with a button dial) on the side of the top radiator hose next to the thermostst housing. The outside air temperature was in the low 70's. I drove the car for over an hour and it showed a steady reading -- did not move. The guage goes from 210 to 250 with only one hash mark in between, so I'm guessing it was reading about 212-215 deg. F.
I stopped the car with the engine running and popped the hood. The thermometer read 172 deg. F. I continued to drive the car and when I stopped and shut it off, the temp guage read about 205-208 deg. F and the thermometer read 175 deg. F.
Temp Guage Thermometer
at idle 212-215 172
stopped 205-208 175
Can anyone tell me if these temperatures make sense and how to correct the guage reading. I've heard you can put a resistor in-line from the temp sender, but how do you know how many ohms???
Thanks,
Jim #33086
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