How often should the rear cooling fan run?

Mine seems to run quite often after I stop. And having just bought the car, I'm wondering if this is normal, or means there is a problem. Two days ago I drove for a while at high highway speeds, but never above 4000 rpm in any gear, then spent 10 minutes driving gently to my destination in town and parked. The fan started up and ran for at least 15 minutes. After the first 2 minutes, I checked the temperature shown on the dashboard display, and it was somewhere between 80 and 90 Celsius (176 and 194 Fahrenheit), which I would not think is too hot. And a day ago, after maybe 90 minutes of similar highway driving, I did about 15-20 in town. Three or four minutes towards the end was admittedly much more spirited, but I never got close to the red line. Then I drove for another minute parked, and the same thing happened with the fan. On both days, it was dark, and the outside temperature was about 15 -17 Celsius (59 - 63 Fahrenheit). And on both days, I did a lot more highway driving, but when I pulled off the highway into a gas station, this did not happen. It was only when I finished a stint driving in town. Is this fan activity normal? And if not, any ideas what could cause it? Thanks for any insight into this!

Check your engine compartment temp sensor, it may have fallen out of it grommet and is lying on the engine. It's between the right side intake runners above the a/c compressor.

I think the more significant issue is that you're on the metric system.

+1 for Ahsai - I had exactly this issue and discovered my sensor had dropped out of the (rather insecure) holder and was sitting next to the exhaust manifold - hence the fan running. Took 30 seconds to pop back into its place and I have never heard the fan running since.......

Thanks for the helpful advice! I will check the sensor position tomorrow.

Good news and bad news: The good news. My local specialist believes it is normal for the fan to run 15 minutes after driving in the city. The bad news: I drove home, turned the engine off, and the fan came on. And then, while I'm sitting there looking at something else, a warning message appears on the dash board: "engine fan failure" or something like that. And the fan keeps running ... . Surely "engine fan" (or perhaps it said "engine ventilator" or "engine ventilation fan") means the one in the rear spoiler, no? What can this mean???? (Further details: The message appeared exactly where the message "consider distance with remaining fuel" (or something like that) appears. As with that message, it said "OK" at the bottom until I pulled back the stalk to confirm. Then no more information about the fan. At the time, the key was in the car, turned as far clockwise as it goes without the engine starting, and the door was open.)

P.S. About the engine temperature sensor, where exactly is this? I had trouble asking my local specialist if this might have fallen out, perhaps because I thought it's attached to the underside of the engine lid. (Or is it?) Anyone have any pictures? (I searched, but there seem to be no threads in the 996 forum with such a sensor in the title.) Update: I think I found it - well, a picture of it: http://www.6speedonline.com/forums/9...n-working.html

It was the engine compartment temp sensor. Problem solved. Thanks for the helpful advice!!! It might have taken a long time to figure this out otherwise.

Always good to see a story with a happy ending. Congrats!

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Good to hear that. The sensor has failed or it just fell out of the grommet?

I have complete opposite. I have never heard my engine compartment fan running. Is that bad? No matter how long or short a drive...it has never come on that I know of and never runs after car shuts off.

I'd have that checked out. The fan pretty much comes on after any drive. Unless maybe you live in Siberia or Buffalo, so it never gets hot enough?

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I live in Florida. The temp gauge on the dash never goes past where normal is though? I will have it checked...

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Cuda, are you sure your sensor has not fallen off? Mine runs only if I park it inside a small garage after a hard drive. If I park it in an open area, the fan doesn't turn on. The other case is if I leave the car idling for a long long time that the coolant fans are on high, the engine fan will go on as well.

In 6 years of ownership mine came on for the first time this year. I realized the sensor came out of the grommet. Never came on during track days.

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Just went out and checked, and looky what I found, crammed down into the engine block area! Dang, the rubber grommet is gone. The second pic is from Pelican's web site, so others reading this thread in the future can see where it belongs. Anyone got a part number for the rubber grommet? Does Pelican carry it? (I searched, but couldn't find the grommet on their web site) .

Hehe, what prize did I win? the grommet is 99311053001

Here, you win the ENTIRE Cracker Jack prize collection! . Just now placed my grommet order, so should be hearing less fan soon! (I put "grommet" into Pelican's search bar, but it failed to find this part... you must have a secret inside Pelican contact) .

Lol Btw, I would suggest you order two if it's not too late. Also when you install the grommet, insert the sensor into it first and install as one piece onto the header. If you install the grommet first and push the sensor in, the grommet will likely fall into places you can't reach.

Ah, poop, already completed the order, and the shipping is more than the part. Oh well. My pile of "parts I may someday need" is getting too big, anyway. It sure looks easy for the grommet to come loose from the intake manifold , but I'm surprised that the grommet falls off of the sensor.

Oh, here's a pic from last year when I was mucking about with the engine, and the sensor was clearly in place at that time: .

Yes but the grommet was already off it's mount though. Maybe the engine vibration then knocked off the grommet from the sensor later.

^^^ Good eyes. When I zoom in on the pic, you are right... the grommet is keeping the sensor from falling down, but has slipped loose. A number of track events since then, so I imagine that could have jarred things loose.

Quit calling the intake manifold a "header"!

Oops, tying too late hahah. Meant to say intake runners.

I guess I'll just zip tie it up for now.

Yeah, that's a good idea. By running the fan less, you're taxing the battery less too after the engine is turned off. Less wear on the fan motor too obviously.

Based on the comments earlier in this thread, my fan motor has used up 8 of its 9 lives.

I don't seem to have noticed my fan ever running... would I be able to see it running if I open the engine hood, or does it turn itself off? I've had the car a few weeks, and it's been in the 80's and 90's here. Also, my engine temp consistently points to the "0" on the 180' mark on the temp gage (it's consistently just to the right of the mid-point, so about 3/5 of the way to max temp). Is that normal? Maybe a blown fuse on the fan?

Most likely it's normal. There should be a warning msg in the instrument cluster if the fan doesn't work as intended.

Still waiting for the grommet to show up from Pelican. Odd, now that I moved the sensor off of the engine block, now I get an "Engine fan Failure" message on the dash when I'm at a stop, idling. Never got that when the fan was running after every drive.