Engine coolant temperature based on climate control setting

Oisiaa-

It's interesting that someone else has noticed this. Yes I believe you are correct. I believe the engine computer is compensating for the significant amount of heat that can be removed via the heater core, and the highly efficient low heat capability of the engine.

Are we both talking about the 1.4L? While I haven't charted the results, I also believe that higher heat usage directly corresponds to about 2 mpg loss in fuel economy. Makes sense if the engine is tryino to hold a higher temperature for emissions reasons.

carbon02 said:

Oisiaa-
I also believe that higher heat usage directly corresponds to about 2 mpg loss in fuel economy.

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Nope, that loss of MPG is due to longer warm up times in colder temperatures. Rest a trip on your DIC in the winter, think you will be shocked to see how low your MPG is the first 5-10 minutes of driving. That times X number of days really brings down your monthly averages.

I monitor my engine temp routinely. I haven't noticed an increase in the temperature when running my cabin heater, even with the blower on full. What I have noticed is that lower engine loads result in higher temperatures and higher engine loads can result in dramatically lower (185 F) engine temperatures.

obermd said:

What I have noticed is that lower engine loads result in higher temperatures and higher engine loads can result in dramatically lower (185 F) engine temperatures.

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Same thing here, fully warmed engine will cool 20F+ when you start driving up a hill. Amazing how that electronic thermostat works.

In my diesel the engine seems to run in the low to mid 80C range except when climbing a long steep hill behind another vehicle when I have seen as high as 91C. Outside temperature seems to have no affect on it. Mind you we don't have a lot of times when the heater actually turns on, it is mostly the cooler that is on.

Aussie said:

In my diesel the engine seems to run in the low to mid 80C range except when climbing a long steep hill behind another vehicle when I have seen as high as 91C. Outside temperature seems to have no affect on it. Mind you we don't have a lot of times when the heater actually turns on, it is mostly the cooler that is on.

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Wow, the diesel really runs cool! That's only 176F!