Is this normal ?

satelite

satelite

Senior Member
I was performing some normal maintenance on my 53 PU and noticed while checking temperatures with an IR Gun that the right (passenger)
side of the engine runs 20 to 25 degrees cooler than the left !
I took the readings with the engine at normal operating temperature at the thermostat's and at the temp sensors. I have 180 degree thermostats that actually test within a couple of degrees accuracy. The
truck never overheats and runs very well. Anyone else have this situation ?
Don in SC
 
I've not checked my engine, but it doesn't surprise me that the two sides are different temperatures since the only part of the cooling system they share is the radiator. The amount of crud in the water jacket may be significantly different from side to side and the water pumps may not be equal causing one side to be cooler than the other.
 
It is not at all uncommon to have temperature differences because of crud as mentioned above, but a number of other factors such as coolant flow turbulence, heat differences between cylinders from any variation in actual combustion timing and intake flow and exhaust flow characteristics. You can also have temperature reading differences with the IR gun based on the color of the spot on which you are reading.
 
As far as Flatheads go, it has been my experience over almost 50 years of playing with them, that everything and nothing is normal with them and no two are alike in their normality's...:eek: Another thing I learned about flatheads in particular is; if it ain't broke, don't fix it and, don't go looking any problems because, if you do, they will be sure to find you. As long as it doesn't overheat and runs well, I'd let it be...;)
 
I'm really surprised to hear that the color of the item aimed at with the IR gun would make a difference in the reading. Does it have to do with light absorbtion of the different colors ?
Don in SC
 
Satelite;
Hey I just saw where you are from my son & his family live in simpsonville.
Getting back to the flathead yes that is normal to have one side warmer.Just now I can't remember what side is warmer .
There was some talk on here in that it has to do with the casting of each side that they are not exactly the same.
 
satelite said:
I'm really surprised to hear that the color of the item aimed at with the IR gun would make a difference in the reading. Does it have to do with light absorbtion of the different colors ?
Don in SC
Click to expand...

The fancy word for it is EMISSIVITY. basically an object which is flat black emits more infrared for a given temperature than something silvery. all other colors are somewhere in between.
At my old job, from which I just retired from, I used to re-calibrate infra red sensors. we used an electric surface plate that had a contact thermometer to measure it's actual temperature . Every so often, I used to have to re paint the face with a new coat, if it ever got smudged or scuffed.
So yes, IR guns are sensitive to the surface that you are measuring. better one have a off set that you can set to allow for this problem.
 
Last edited:
Thanks RandyZ that helps me understand the phenomina. I will have to be more selective how I use my IR gun.
Don in SC
 
You must log in or register to reply here.
Back
Top