What Overheating Looks Like In Data

So one of the things I'm doing on this trip is collecting all sorts of engine data at all times while driving. The primary purpose of that is to correlate it with GPS data and create the maps you see on the page. If you open them in Google Earth, you will see my vehicle speed as the height of the graph produced, and the RPM is represented by the blue-green colors.

You can also do other things with the data. Look at this data. This is the temperature of the engine, and the number of times the engine has been that temperature. Readings occur about every two seconds, so if a certain temperature has happened 1000 times, then the engine has been at that temperature for about 2000 seconds, which is about a half an hour. For brevity here I have only shown even numbers, and only temps above 90. This data includes all my driving since leaving Juneau.

90.0|1311
92.0|15924
94.0|35335
96.0|23113
98.0|6402
100.0|3208
102.0|1339
104.0|888
106.0|160
108.0|5
110.0|6
112.0|2
114.0|2
116.0|42
118.0|19
120.0|4
122.0|8
124.0|10
126.0|26
128.0|64

So normal operating temperature on my engine is between 90 and 100 degrees, and this is celcius, so that's just under the boiling point of water. Of course the contents are under pressure, so the boiling point would be a little higher, and also we use coolant, with a much higher boiling point. All together, I spent 48 or so driving hours within that normal range.



Above the normal 90-100 degree range, you see there are small number of readings between 108 and 128, with a small bulge around 116-118, and a bigger high end bulge at 128. The boiling point of coolant is somewhat higher, at about 187 celsius or higher, which leads me to believe that 128 is about as hot as it could get. Perhaps at that temperature, the coolant boils in the engine block, which produces enough convection action to cycle through enough coolant to cool down the radiator to 128.



So that is what it looks like when an engine overheats. The temperature went up at about one degree every five or ten second, starting probably at the moment of failure of the water pump. The bump in data at 116 is interesting. It may be readings from when I had the engine idling, or stopped one of the three times I stopped. I spent about six total minutes driving at high temperature. I am glad I didn't drive longer. I saved myself a big repair.