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Driving with heater on?

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Old Apr 29, 2009 | 02:57 AM
  #1  
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Driving with heater on?

Would driving with the heater on help the engine any? I know it works when your car is overheating, so in theory, it should also vent the heat during normal use as well right?
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Old Apr 29, 2009 | 04:06 AM
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Well typically your suppose to turn the heat on and allow coolant to flow through the heater core to cool it down some if its overheating, its a longer process for the coolant to flow through the engine and allows it to run at a lower temp but honestly why whould you need to do that? If its not overheating then dont worry, it should run cool enough, worse comes to worse you can put a lower temp thermostat in it but it might take forever to warm up the engine and I wouldn't go that route unless your racing all the time and even then its not necessary.

I always had a method since I have a Z32(vents terribly) and its 19 years old now, after driving it pop the hood a little and let the heat out, saves the wiring/hoses a little bit from wearing down.
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Old Apr 29, 2009 | 10:13 AM
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I was also wondering about this as well. I used to do this in my old cars and it seemed to help. Was never sure myself. I still do it in my 8 just in case
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Old Apr 29, 2009 | 10:45 AM
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Using my Cobb Access Port, I monitored turning the heat on when driving and it ran much cooler.. Right now I have all OEM radiator and everything, just running 65/35 distilled water to coolant, with some redline water wetter. Also removed all the insulation inside my engine bay since I don't drive the car in the winter. The heater on helped a lot. Below is the following stuff I recorded.

65 Degrees Out during the test

Heater OFF
Cruising/City Driving - 200-205
Highway/HighRevs - 210-215

Heater ON
Cruising/City Driving - 180-185
Highway/HighRevs - 196-205

Hope this helps.

Last edited by Zelse; Apr 29, 2009 at 11:08 AM.
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Old Apr 29, 2009 | 10:56 AM
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Ya I have also thought about this, but can't notice any change whatsoever with the heat on or off. With the heat dial set to the heat side of things, and the fan speed dial set to zero, the cabin seems to heat up anyway, without wasting any power for a fan.


Also just a side note for those of you who haven't read the owner's manual; the AC compressor automatically turns on when you do any of the following things:

leave climate control in the feet only position
leave climate control in any position with front defroster on
turn on the ac compressor switch. (obviously).

Do not do any of these things during hard driving unless you want to have horses syphoned from under your nose.
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Old Apr 29, 2009 | 11:01 AM
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Originally Posted by renesisgenesis
Ya I have also thought about this, but can't notice any change whatsoever with the heat on or off. With the heat dial set to the heat side of things, and the fan speed dial set to zero, the cabin seems to heat up anyway, without wasting any power for a fan.


Also just a side note for those of you who haven't read the owner's manual; the AC compressor automatically turns on when you do any of the following things:

leave climate control in the feet only position
leave climate control in any position with front defroster on
turn on the ac compressor switch. (obviously).

Do not do any of these things during hard driving unless you want to have horses syphoned from under your nose.
AC compressor also turns off automatically when you are WOT...
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Old Apr 29, 2009 | 11:04 AM
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The cabin is hot enough as is.............. don't you remember all the complaints about the AC?

If your not over heating, then no need to turn on the heater. If your over heating you shouldn't be driving it period.
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Old Apr 29, 2009 | 11:15 AM
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Originally Posted by Razz1
The cabin is hot enough as is.............. don't you remember all the complaints about the AC?

If your not over heating, then no need to turn on the heater. If your over heating you shouldn't be driving it period
.
thanks razz, no one could of said it better.
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Old Apr 29, 2009 | 11:22 AM
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^

Thanks for that info Zelse!
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Old Apr 29, 2009 | 11:24 AM
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Yeah... pretty sure the factory cooling system shoulda been sized correctly

Maybe move the heater core to the outside of the car... get more cooling!
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Old Apr 29, 2009 | 12:51 PM
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Yeah no problem. Granted the difference is that I took out engine bay insulation and I have red line water wetter..but it can't help that much.. :x Or does it? lol.

But yeah, Razz said it best. :D
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Old Apr 29, 2009 | 01:12 PM
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why is it exactly that running the heater would allow the motor to run colder?

Not disagreeing at all, just curious how this would happen.
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Old Apr 29, 2009 | 02:03 PM
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Originally Posted by renesisgenesis

Also just a side note for those of you who haven't read the owner's manual; the AC compressor automatically turns on when you do any of the following things:

leave climate control in the feet only position
leave climate control in any position with front defroster on
turn on the ac compressor switch. (obviously).

Do not do any of these things during hard driving unless you want to have horses syphoned from under your nose.

When you say the AC compressor is on, is that essentially the same as having the AC on and running with the fan speed at 1-4? What if the climate control is set to feet/defroster but the fan dial is at 0?
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Old Apr 29, 2009 | 02:14 PM
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Originally Posted by renesisgenesis
why is it exactly that running the heater would allow the motor to run colder?

Not disagreeing at all, just curious how this would happen.
The heater works by running coolant through a heater core (heat exchanger just like the radiator)

This means that you have another really small radiator being used to help remove heat from the coolant when the heater is on
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Old Apr 29, 2009 | 02:40 PM
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Originally Posted by streetsrx8
When you say the AC compressor is on, is that essentially the same as having the AC on and running with the fan speed at 1-4? What if the climate control is set to feet/defroster but the fan dial is at 0?
These are good questions. It does not matter if you set the dial to zero or not, if you engage the front defroster and/or the feet only setting, your motor automatically begins running the AC compressor. I do not know enough about AC compressors to know how much the fan speed level effects your AC compressor power leaching. The owner's manual doesn't seem to specify the effects of the fan speed setting. It simply states that the compressor will start running if you engage any of the mentioned settings; so I am thinking it is probably regardless of the fan speed setting.
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Old Apr 29, 2009 | 03:07 PM
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I too would like somebody with some smartz to tell me if the fan speed makes a difference. I know my Silverado cycles the compressor on/off when set to 1, but I never feel a change in the 8.

Hell right now I don't even have a heater. I need to do that solder fix with the temp **** but it never gets cold enough in Houston to justify all of that work. Maybe this fall I'll get to it, doubtful though.
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Old Apr 29, 2009 | 03:24 PM
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Originally Posted by renesisgenesis
These are good questions. It does not matter if you set the dial to zero or not, if you engage the front defroster and/or the feet only setting, your motor automatically begins running the AC compressor. I do not know enough about AC compressors to know how much the fan speed level effects your AC compressor power leaching. The owner's manual doesn't seem to specify the effects of the fan speed setting. It simply states that the compressor will start running if you engage any of the mentioned settings; so I am thinking it is probably regardless of the fan speed setting.
Thanks for the reply. Unless I'm mistaken (and I probably am) the AC compressor can also effect gas mileage as well, right? I am going to have to start leaving it set to feet/vent or vent only and see if I notice a difference.
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Old Apr 29, 2009 | 08:04 PM
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Thats was going to be my thing. To many factors at play. How much does running the fan drain on performance. What are you trying to accomplish? Because in order to make power you have to create heat. Heat is not exactly a bad thing. If the motor is too cold the heat of compression and combustion is lost therefor loosing power. Thats why when you dyno a vehicle you have to make three runs to make sure consistancy, when to cold the motor will run poorly. Let the radiator do the work. The thermostat will regulate the temperature of the coolant. Even with the heatercore cooling down the exterior coolant before it enters (before or after the radiator) the coolant will stay in the motor untill the thermostat opens and flows.

If it aint broke stop trying to fix it.
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Old Apr 29, 2009 | 08:26 PM
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/\ What you said... except for Premix
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Old Apr 29, 2009 | 09:03 PM
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From: Fort Lauderdale, Florida
It's hot enough in FL as it is
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