Temp gauge reading low
Discussion
Hi all
Finally dragged my wedge out of the garage after it hasn’t turned a wheel for about 8 months
After a good check over I went out for s quick run
All pretty good - bit of steering wheel shake - possibly flat spotting on tyres after its long lay up ??? Which eased after a few miles but not gone away completely but also got temp gauge not reading correctly
Gauge has always seemed to read low (about 80-85 c ) but now reads around 70 c in normal running
Thermostatically controlled cooling fan is cutting in ok and it seems plenty hot enough under the bonnet so I’m guessing a fault with either the sender or gauge
I’m guessing the sender is just a temperature controlled variable resistance- any ideas on what values I should be getting at various temps so I can test it ??
Thanks Ron
Finally dragged my wedge out of the garage after it hasn’t turned a wheel for about 8 months
After a good check over I went out for s quick runAll pretty good - bit of steering wheel shake - possibly flat spotting on tyres after its long lay up ??? Which eased after a few miles but not gone away completely but also got temp gauge not reading correctly
Gauge has always seemed to read low (about 80-85 c ) but now reads around 70 c in normal running
Thermostatically controlled cooling fan is cutting in ok and it seems plenty hot enough under the bonnet so I’m guessing a fault with either the sender or gauge
I’m guessing the sender is just a temperature controlled variable resistance- any ideas on what values I should be getting at various temps so I can test it ??
Thanks Ron
I had the same problem on a previous wedge and this is how I solved it....
I took the wire off the back of the sender and touched it to earth briefly with the ignition on. The gauge should shoot up to full scale telling me the gauge is fine. I then changed the sender to a new one and at normal running temperature the gauge reading was higher than usual eg. over 100. Now, using an inline resistor of various values one at a time I reduced the reading to 90 when engine is at normal temperature, and it’s all set. I can’t remember the value of the resistor I used off hand but I did note it down somewhere. The fan should now kick in before the gauge reaches the red mark. Worked fine there after. I hope that makes sense.
Tony. TCB.
I took the wire off the back of the sender and touched it to earth briefly with the ignition on. The gauge should shoot up to full scale telling me the gauge is fine. I then changed the sender to a new one and at normal running temperature the gauge reading was higher than usual eg. over 100. Now, using an inline resistor of various values one at a time I reduced the reading to 90 when engine is at normal temperature, and it’s all set. I can’t remember the value of the resistor I used off hand but I did note it down somewhere. The fan should now kick in before the gauge reaches the red mark. Worked fine there after. I hope that makes sense.
Tony. TCB.
Rockettvr said:
Hi Tony
Good to see you’re still active on here
A quick test proves you right - disconnect lead and gauge reads zero
Touch to earth and gauge is off the scale
Think I’ve found a replacement- I’ll order one up and if ok I’ll post up a link
Yes still here, just about. I’ve actually just bought another 400SE that needs a bit of work doing but I’m getting there slowly.Good to see you’re still active on here
A quick test proves you right - disconnect lead and gauge reads zero
Touch to earth and gauge is off the scale
Think I’ve found a replacement- I’ll order one up and if ok I’ll post up a link
Once you’ve established the temperature gauge is working ok, change the sender and see what reading you get then. If the reading is higher than expected, it can be reduced to the correct level by using inline resistors as explained earlier. All the best.
Tony. TCB.
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