Fleetwood Meadow

IR temperature reading for engine

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I have read so many different answers to this that I decided to ask the wise folks here. I am trying to see where my gauge is reading in relation to the engine temperature but I’m not sure where exactly where I should be pointing the gun. Some say to point it to the upper radiator hose. Some say to point it on the metal of the water pump. Some say point it on the head. Each one of those spots produced a different temperature, especially the spot on the head near the exhaust port. Is the coolant temp going to be the same temperature as the metal engine? Where is the best spot to check the engine temp?

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You will find it hottest around and close to the spark plugs. My engine temperature increases towards the rear (straight 8, as it gets further away from the coolant inlet at the pump). The temperature beside the gauge sender is the temp. you will see inside, obviously. My IR thermometer also doesn't give reliable readings near the HT wires.

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An IR temp gun is a great tool for getting a quick measurement, I’m not saying this is what happened here but it is a case of measurer beware. These guns can be easily fooled by anything shiny e.g chrome, stainless steel, even high gloss paint and will give an inaccurate reading. Also the further the gun is held from the surface the greater the area the gun averages the temperature over. Up close you get a pinpoint but the further you move away the larger the area being averaged becomes.

If measuring the temperature accurately is important you probably want to look at a touch pyrometer or use a thermocouple with your multimeter.

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4 hours ago, Fleetwood Meadow said:

I have read so many different answers to this that I decided to ask the wise folks here. I am trying to see where my gauge is reading in relation to the engine temperature but I’m not sure where exactly where I should be pointing the gun. Some say to point it to the upper radiator hose. Some say to point it on the metal of the water pump. Some say point it on the head. Each one of those spots produced a different temperature, especially the spot on the head near the exhaust port. Is the coolant temp going to be the same temperature as the metal engine? Where is the best spot to check the engine temp?

 

My take is that you are wondering how accurate your temp guage is ?? if you can see where the temp probe is located on the engine thats where you want to point your IR gun, close is better.

 

If you are looking to see how hot the coolant is then point your IR at the radiator inlet pipe/spout.

 

If you are looking to see how well the radiator is working, point your IR  at the inlet pipe then the outlet pipe and note the difference between temperatures, generally you should get a temp drop about 15 degrees C for an efficient radiator.

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Hchris:

A temperature drop of 15 degrees C equates to about 27 degrees F.  I typically see a drop of about 15 to 20 degrees F with a recored radiator.  

These IR guns are very useful in many applications.  

Joe

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1 hour ago, Joseph P. Indusi said:

Hchris:

A temperature drop of 15 degrees C equates to about 27 degrees F.  I typically see a drop of about 15 to 20 degrees F with a recored radiator.  

These IR guns are very useful in many applications.  

Joe

 

Whoops, yes should have degrees F

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