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Hey guys, :7: been concerned about this.....
How often do your fans come on. I can`t think of the word, but it`s the fans that kick on when the car needs a bit more coolin.
Mine seem to come on speratically here and there quite often. I donno if this is the norm or what, just kinda wondering. On start up I get (i think) ATF fluid temp light that lights up but then goes off, never comes on while driving though. :8:
Haven`t had this happen with any of my other cars.


P.S. the a/c is off as well as the heater.

Thanx
N8
 

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Your fan behavior sounds normal. When coming home, I drive slowly back a gravel lane & then slowly up my driveway. That short distance at low speeds (no "ram" air through the radiator) is often enough to make the fan run, even on moderate days- say, temps in the 50's. I usually park & let the engine run until the fans stop on their own- which seems to take longer than my other cars. Sometimes both fans activate.

The ATF temp light at startup is normal, probably just a self-test.
 

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Tokyo's between my toes
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*G* I used to take my Escort to the top of a driveway that climbed a bit more than 200 feet over 1/4 mile or so. I would sometimes hear the steam bubbling into the overflow bottle (sounded like someone making espresso).

I finally wired a switch into the fan relay so I could turn it on _before_ the climb - also handy at various other times.
 

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I noticed those fans or fan (do have two, also) run fairly often when at fast food drive thru's and stopped in traffic. I'd say every minute, or so, I will hear the fan(s) switch on.

Once warmed up it doesn't seem to make much difference whether the temps outside are in the 80's or 40's F. I don't have a lot of miles on my OBS yet, at only 5150 now, so not a lot of experience with that. It probably is more frequent on hot days and I just think it seems the same.

For example, last night the temp was 50 F and the fan turned on about 10 seconds just after parking in my carport after a long drive. I've already gotten accustomed to giving it time to cycle itself on and off before turning off the ignition.
 

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waiting for fans to stop

Is it really important to wait for the fans to stop when parking? I can see that it prevents the engine being left suddenly without cooling, but to my mind if the temp gauge in in the normal spot it shouldn't really matter. What do the engine guru's think?
 

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My fans kick on all the time. It can be 90, it can be 30... the fans will run for a few seconds if I slow or stop. I always let the fans turn off before I shut the car off. May not matter though. I'm not sure.
 

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Re: waiting for fans to stop

Jondalar said:
Is it really important to wait for the fans to stop when parking? >8---8< What do the engine guru's think?
I don't qualify as a guru but my reasoning for letting the fan(s) spin then stop before pulling the key is simply because I'm babying my new toy far too much. :D

That might change when 2005 rolls around. I'll make that my New Year's Resolution, to treat it more like my previous cars and trucks. It's on its own thereafter!

Fact is, I've only now begun to get startups of the engine with a crank or two of the starter motor. It was still taking three or four turns (or the sound of turns) before it would fire up, during the first couple months; I'm guessing from the tightness and newness of the engine. Been 16 years since my last really new car, so I don't even remember how that usually goes. My old truck was starting up at the slightest turn of the key when it was about 7 years old, then got a tiny bit finicky toward the end.
 

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likewise no guru, just stumbling fool, but....

no matter whether or not the coolant is hot enough that the fans run at time you shut it down, once the water pump shuts down, the temp of coolant in the heads goes WAY up due to no circulation. in light of this effect, i doubt that the 10-15 degrees difference you might get with running the fans for a minute or 2 (being generous...) would make a difference. i don't do this and had honestly never heard of it previously.

of course, all the above changes if you have a turbo on your car, esp if the bearing section is not water-cooled....you want to let it idle for at least 20-30 sec whenever you shut it down to bring bearing section temps down before the flow of cooling oil shuts off when you kill engine.
 

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and Nate, the behavior is absolutely normal...it just indicates that the thermo sensors are sensitive enough that they react to relatively small changes in temp.
 

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cptoversteer said:

you want to let it idle for at least 20-30 sec whenever you shut it down to bring bearing section temps down before the flow of cooling oil shuts off when you kill engine.
My understanding is, you need to keep the oil pressure up as long as the turbo is still spinning, but that might be old information.
 

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yeah, sorta. the bigger issue is to keep cool oil flowing so residual oil in bearing area doesn't turn to rock from heat when the flow stops. altho Corky Bell, one of the turbo pundits since late 70s, says this is bull. basically, water cooled center bearing sections have all but eliminated problem


i think the turbo will have effectively quit spinning in other than an unladen idle mode well before you shut off engine, unless you accelerate hard up your driveway like you was in an Escort...
 

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Ayy, now yer talkin serious performance! Why, I could put a 12V fan facing backward on the roof and shave two seconds off my 1/4 mile time!












































...not true... slips quietly back into the Sea of Japan...
 

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Discussion Starter #14
thanx for the massive input guys......:20: Pretty funny hearing everyone go off;) :D

With my turbo on the Saab (when I had it), it is always good to let the car idle to cool down for abit after a "spirited drive".
The turbo could get soo hot that if shut off right away you could get warping. Trust me on this one.....it happened to me.:mad: the turbo started to wobble whilst spinning making a chatterng sound under heavy boost. Long story short......wobbling started to chip the blades inside the housing, if not fixed....metal shavings in engine then engine break. 1000 buckskins later for a new turbo job!

So if turbo hot, :9: let cool for a few minutes.;)
 

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Tokyo's between my toes
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So why not an electrically-operated water pump that can still turn as the fans run after the car is off if temps require it - instead of everyone putting them on the timing belt so a water pump job = timing belt job?
 
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