Nerd Alert!2009C2S 74K miles
Using my Durametric, I tracked the following from a cold start (ambient temp was 32 F):
RPMs
Car speed MPH
Engine Temp (water temp but Durametric shows as “engine”)
Oil Temp
Catalytic Converter Temp
Why did I do this? Um, I dunno, ‘cause I am a nerdy geek. But I, like others, have wondered about oil temps on cold start ups. It appears on our gauges that oil temps lag way behind water temps. But as the graph shows, oil lags water temp by only about two minutes and track closely together. So some observations:
1- Oil temp lags water temp by about two minutes but warm up equally together
2- Oil temps and water temps stabilize to about the same temps under “normal” non-aggressive driving
3- Oil and water temp rise at a controlled constant rate regardless of load/RMPs/speed
4- You can “hit it” after about 10 minutes of easy driving (starting out at 32F) as oil and water temps are near their stable maximum.
5- I did this earlier this winter and witnessed the same, linear controlled rise in water temps under a different driving situation (I did not track oil as the Durametric tool had me a bit confused)
6- Cat temps made no sense to me except they get hot fast and then seem to drift without much regard to other dynamics
Driving situation: Car was kept outside over night and I started it about 10:27 in the morning when ambient temp was 32 F. I waited until the car’s pitch changes (about 20 seconds) and backed out of my driveway. Then I drove gently through stop signs, up a few rather steep short hills, then to a few red lights, and then onto the interstate at 10:37. I kept RPMs below 3500 until I hit the interstate.
Time: Elapsed from engine start to stabilized temps was about 12 minutes and I shut down the computer after about twenty minutes.
Air Temperatures: I did not display any air temps in the chart. Ambient temperature was 32 degrees F. I tracked a few different “Air Intake” buckets and while one sensor tracked between 32 and 34 degrees F (obviously external, ambient temp), others were very different although they all started out at 32 F. One swung from 32 F to a high of 193 F and tracked closely with vehicle speed and RPMs dropping to 32 F when vehicle speed was 0.
Catalytic Converter Temps: I recorded both left and right bank but showed only the left in the graph, as both read virtually the same.
Peace
Bruce in Philly
Click here to download a larger JPG:
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