engine runnng temperature.

[belvedere666]

recently purchased an infrared thermometer to check the running temperature of my 218.

i'm getting some VERY different readings throughout the car.

Radiator cap gauge is reading 170ish. (aluminum radiator)

Temp gauge at the water bypass is reading 170. (aftermarket)

Dashboard gauge is just a little over the middle line but not close to "HOT".

infrared thermometer is reading between 205-215 at the rear of the block

and about 170 in the middle section of the block. (both taken from the top of head)

as far as i can tell the water is flowing through all the passages.

 i have a 180 degree thermostat was new and working ( i tested it) before i installed it.

Has anyone tested temps in these areas?

Do my numbers and the differences from one section to another seem "normal" or "abnormal"?

[keithb7]

I performed a similar test with an IR thermometer. My temps were all over the place too. I suspect its too sensitive and takes a pinpoint reading very accurately. There are going to be hot spots. The coolant flows past those hot spots and draws the heat away. I suspect a more realistic measuremememt of the coolant temp is as it flows past a sensor. Sort of like a rock laying in river bed. The volume of water flowing around it, mixing as it flows. Giving an average reading. Not a laser pointing at various pinpoint areas of hot steel or aluminum on parts the engine. 

 

That’s my theory. 

 

My findings are here:

 

Edited June 16, 2019 by keithb7

[busycoupe]

The rear of the head was hotter on my engine than the front or middle of the head, but not as much as you report. Mid head on mine was 170 deg. rear of the head was 190 deg.   It is possible that your water distribution tube is partially blocked.  However, if the engine runs OK and nothing is above boiling temp then you are probably OK running it.  

[thebeebe5]

Depending on the condition of the motor...   as mentioned, plugged/rotted water tube?   

I’ll say from experience upon tearing down my ‘37 I found an almost non existent water tube, and enough crud built up in the water jacket at the floor and around cylinders No. 5-6 that there couldn’t have been much circulation back there.  Engine ran hot  even in cool weather.