Temp Gauge Reading

[Guest kevS7]

Hi All,

Been having probs with cooling system for a while now. I have fitted a Mondeo expansion tank and this seems to have done the trick. My problem is that the temp gauge reads 130 deg and my fan stat says 80 deg. The engine does not over-heat but I would like to find out the correct temp of the engine. Any advice please????

Thanks ,Kev

[ibrooks]

The sender and gauge must match or they will read incorrectly - looks like this is what you have. There are several options......

 

If you know what the gauge is (original Sierra? or something else) you might be able to get the correct sender.

 

If not then it would be possible to measure using a variable resistor what resistance it needs to show a given temp range and you might be able to find a sender that matches. You connect the resistor instead of the gauge and turn it to run the gauge through it's range noting the resistance at certain temperature points on the gauge. Plot this lot on a graph to see if it's linear or maybe logarithmic and you then know what you're asking for.

 

Failing that as long as it's consistent you can use another method to take a set of readings of the engine temp (turkey thermometer in the top hose?) and look at what yours reads so you know for a given reading on your gauge what it really means.

 

Ultimately the final solution is to buy a replacement gauge and sender pair that you know will read right from the word go.

 

Iain

[fry61]

Where are you Kev, may be able to help with an electronic non-contact thermometer.

[Guest kevS7]

The sender and gauge must match or they will read incorrectly - looks like this is what you have. There are several options......

 

If you know what the gauge is (original Sierra? or something else) you might be able to get the correct sender.

 

If not then it would be possible to measure using a variable resistor what resistance it needs to show a given temp range and you might be able to find a sender that matches. You connect the resistor instead of the gauge and turn it to run the gauge through it's range noting the resistance at certain temperature points on the gauge. Plot this lot on a graph to see if it's linear or maybe logarithmic and you then know what you're asking for.

 

Failing that as long as it's consistent you can use another method to take a set of readings of the engine temp (turkey thermometer in the top hose?) and look at what yours reads so you know for a given reading on your gauge what it really means.

 

Ultimately the final solution is to buy a replacement gauge and sender pair that you know will read right from the word go.

 

Iain

[Guest kevS7]

Thanks Iain.

I have a Smiths guage and a standard Sierra sender unit. I will get a sender that is compatible.