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Cool down in hot temps:

Old 05-25-2010, 07:23 AM
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Cool down in hot temps:

Living in South Florida and driving in rush hour traffic really makes the radiator fan work over time when you shut down the engine. I noticed that when I get out of the car the fan is going like hell for a pretty long time. I found that when I shut down in my driveway wait a few seconds and restart the engine to move it into the garage, that few seconds seems to utilize the radiator flow to cool down more and the fan does not come back on.
Just a thing that I noticed.
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Old 05-25-2010, 07:33 AM
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Just turning the key back on and off again can disable the post-shutdown fan under most circumstances. If the fan wants to run after you turn the car off, let it.
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Old 05-25-2010, 08:18 AM
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The fan will go into "rage mode" when :

The water temp sensor (yea there is one ...) is at or above 102 Celsius.


The computer is just trying to cool your coolant off PLUS your engine (cuz remember, once you turn it off, Coolant will NOT flow,)
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Old 05-25-2010, 09:38 AM
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Let that fan run! The car knows what's best for itself.
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Old 05-25-2010, 12:57 PM
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Yeah, let it run. The one thing you can do to help out is to run the last few miles gently before you stop the car. My longest fan run-ons happened when I ran the car hard in high temps all the way to where I stopped. Just a few miles of easy cruise will bleed off a lot of heat and do the job that the fan has to do otherwise.
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Old 05-25-2010, 03:20 PM
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too bad for you, i guess.

i have my 8 garage parked, and cooled downed by a house fan on a timer.

easy fix to prolong the life of things under that hood when the motor is shut down and becomes a oven...

strikes me odd that you don't want a fan to come on after you shut off your car!
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Old 05-26-2010, 02:06 AM
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You could also try turning heater to max and fan to max to help cool down.
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Old 05-26-2010, 12:21 PM
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Originally Posted by nycgps View Post
...remember, once you turn it off, Coolant will NOT flow
I'm thinking the coolant will still exhibit some flow due to convection. Otherwise having the radiator fan run after shutdown wouldn't seem to make sense.
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Old 05-26-2010, 12:28 PM
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I have this like pretty much every day starting may through october (fan on after engine turn off). I thought there was something wrong with the car, a messing wire or something, but i can see its normal now. Never thought the engine was smart enough to cool itself down after being turned off ;b
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Old 05-27-2010, 08:45 AM
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I bet ewp's are coming at some point.
OD
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Old 05-27-2010, 10:15 AM
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Originally Posted by Nubo View Post
I'm thinking the coolant will still exhibit some flow due to convection. Otherwise having the radiator fan run after shutdown wouldn't seem to make sense.
No, it won't. The convection will be going on at both ends of the coolant circuit, and the opposing pressures will cancel each other out.

Anyway, look at where the radiator will radiate heat if the fan is off and the car isn't moving -- right back into the engine bay. That accomplishes nothing.

I was surprised when my radiator fan kicked in while I was getting the mail yesterday after I parked my car. Never had a car do that before. Well, whatever, as long as it doesn't kill the battery.
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Old 05-27-2010, 11:37 AM
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Originally Posted by fyrstormer View Post
No, it won't. The convection will be going on at both ends of the coolant circuit, and the opposing pressures will cancel each other out.

Anyway, look at where the radiator will radiate heat if the fan is off and the car isn't moving -- right back into the engine bay. That accomplishes nothing.

I was surprised when my radiator fan kicked in while I was getting the mail yesterday after I parked my car. Never had a car do that before. Well, whatever, as long as it doesn't kill the battery.
The coolant in the radiator will cool much more quickly than the coolant in the engine block. That's the radiator's purpose in life. So you should get circulation. Not as brisk as with the water pump, but enough so that residual heat-soak from hot metal components can be dissipated instead of causing the coolant temperature to continue rise after shutdown. It was not unheard of to have boilvers after engine shutdown with belt-driven fans.
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Old 05-27-2010, 11:41 AM
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Originally Posted by Nubo View Post
I'm thinking the coolant will still exhibit some flow due to convection. Otherwise having the radiator fan run after shutdown wouldn't seem to make sense.
maybe a little bit, but I think the main purpose of the "fan on after shut off" is to cool the engine from the outside quicker.

Rotary engines runs pretty hot, yes.

but it also cools down pretty quickly (compare to a piston engine)
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Old 05-27-2010, 01:08 PM
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I've only had my car about 1-1/2 months, but I have never had the cooling fan come on after I shut the car.

My daily drive is around 35miles each way, with the last 2-3 miles being relatively slow backroads in both directions. Must be that last little bit that helps the car cool down.
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Old 06-24-2010, 09:40 PM
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Originally Posted by tcole6 View Post
I've only had my car about 1-1/2 months, but I have never had the cooling fan come on after I shut the car.

My daily drive is around 35miles each way, with the last 2-3 miles being relatively slow backroads in both directions. Must be that last little bit that helps the car cool down.
I've had my car for about 2 months and put about 2500 miles on it. Today was the first time the fan ever came on after shut down...and it was the same drive home from work I've taken every day for the past few months....and the temps here were about 10 degrees lower than they have been for the past week or so.

At first, I feared there was something wrong with my car....but glad to see it is a normal cool down feature of the RX8.
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Old 06-25-2010, 01:03 AM
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If your concerned with your engine temps I'd suggest reading some of the DIY's on here. There's a few like the throttle body bypass, a mod for better oil cooler air flow, etc. I even went and did what most ricers around my town do. Lift my hood about 2" from the hinges so as to let heat from the engine bay exit. Also no engine cover. Get's considerable hotter with headers on.
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Old 06-25-2010, 01:36 AM
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FL

Originally Posted by tcole6 View Post
I've only had my car about 1-1/2 months, but I have never had the cooling fan come on after I shut the car.

My daily drive is around 35miles each way, with the last 2-3 miles being relatively slow backroads in both directions. Must be that last little bit that helps the car cool down.

you live in new jersey, notice the rest of us are in Fl and Cali
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Old 06-25-2010, 08:03 AM
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^...............Jerseys get pretty freakin hot and muggy trust me.

Anyway, let the fan run. When I pull into my garage, I usually just pop the hood to let the hot air out to speed cooling. If the fan is running at that point, it will usually shut off a little bit sooner. I too have a house fan mounted upside down on the garage ceiling that blows past the engine bay. Don't always turn that on, but I do open the hood. I have dampers so no prop stick......making it just a wee bit easier, not that it would be that difficult the other way!

Last edited by Mazurfer; 06-25-2010 at 02:14 PM.
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Old 06-25-2010, 09:07 AM
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^^^ thats what i do just pop the hood
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Old 06-25-2010, 11:43 AM
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Originally Posted by mzbenz View Post
you live in new jersey, notice the rest of us are in Fl and Cali
Yeah, and this week we had 3 days consistently 95-96 F with humidity over 85% and the cooling fan ran for quite awhile each day after shutoff.

Yesterday was back to normal 85 F and no cooling fan.
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Old 06-25-2010, 06:27 PM
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I always suggest vented hoods as they are more of a reliability mod with a bonus upgrade in looks most of the time...
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