"Engine" Temperature Measurement.

[mockingbird812]

Thanks Mike, just what I was looking for. You are right, I want to make sure the gauge is reading close. So would it also be beneficial to hold the IR thermometer at 6" or less from the black electrical tape on the top of the thermostat housing? Also, are the radiator hoses (upper and lower) a good point to measure coolant temperature given their emissivity?

Your information is very beneficial as engine temps are critical to good reliable/non damaging operation. I will be giving a tutorial (with appropriate credit given) to all my friends that use these IR Thermometers as I think they have been mis-using theirs as I have.

[Dusk Blue Z]

Rubber works as an insulator, you can touch the hose when the engine is hot but you don’t want to touch the radiator shell which is down stream.

I took a look at your pictures, I wouldn’t put tape on the housing on that car. Just measure the thermostat housing with the thermometer close to it. The cooling wind from the fan and the built in error factor in your tester I don’t think will change your readings enough to worry about.

Mike

[mockingbird812]

Mike,

So because rubber is an insulator, does that mean it would not be a reliable place to take a measurement? Will take measurements on the sender housing per your instructions. Thanks!

[Kurt S]

I believe the standard place for measuring coolant temps with the IR gun is the thermostat housing.

For calibrating your gauge, just pull the sender unit out and put it in water. Measure the water temp with a thermometer. Compare.
Repeat with hotter water......

[mockingbird812]

I had heard that was most folk's practice - using the thermostat housing. But from what I understand that Mark said, shiny or light colored objects do not give a true reading. My housing is unpainted aluminum.

[Dusk Blue Z]

Sam,

The reading you would get from the upper radiator hose would be an accurate temperature of the surface of the hose not the fluid inside it. I am at a customers site this week and don’t have access to all my reference material which would list the different emissivities for materials and paint colors. The emissivity number is a multiplier for the radiated heat that the radiometer picked up to give an accurate temperature reading. Your unit is fixed at 0.95, the more expensive units would allow you to input the number for your target material.

I think if you read off the top of your bare aluminum housing you would be within 5 degrees of the true temperature.

I am making plans to attend SCR 10. If anyone would like to have me measure their car to check their gauge accuracy just drop me your name and description of your car and I’ll look you up.

Mike

[mockingbird812]

Mike,

Thanks again for your insight. This has been very helpful to me. I have spent a good part of my career in sensors, just in a different part of the spectrum. I can always learn something new.

Good gouge:

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I think if you read off the top of your bare aluminum housing you would be within 5 degrees of the true temperature.

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