[jthomson]

Hey all,



Have dug through many threads on this topic and have learned quite a bit. Fantastic forum! Maybe I missed it but I need an answer to these two quesitons; Are the low speed fans supposed to come on when the engine hits operating temp, ie., around 8 o'clock?



And, is the high speed of the fans engaged w/ac or is it the low?



Right now with no AC, the low speed doesn't come on at all. When idling the gauge will eventually hit 10:00 and the high speed will come on cooling the engine and shut off at about 9ish.



With AC, the LOW fans come on right away. I don't seem to have a problem at speed. If I'm cruising around in town I'll eventually have to hit the AC and the gauge returns to 8:00.



I noticed that my coolant was rather low, about a half inch below the minimum. Topped off and it behaves a bit better around town. Still have to hit the AC. Of course when idling it still hits 10:00.



Amongst other work, the WP was replaced in '07. Records indicate it was a Porsche reman.



I went out and bought a laser temp gun. Even at it's hottest the upper hose measured below 190. The bottom hose around 175. but that measurement was taken only about 3 or 4 inhces from the block inlet. Do I need to measure that closer to the rad outlet?



Finally and as always, any help is much appreciated.



JT

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[flash]

is the belly pan in place underneath the car?

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[tamathumper]

@jthomson, I believe when you switch on the AC, both fans should come on "High".

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[DaveN]

Go to the guide at Clarks Garage, full of info. I thought the one fan came on with AC but then I've been wrong before, ask my wife <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" />

Sounds like the temp sensor at the top left of the rad to me if buggered on the low speed side. You need a big (31mm?) socket for that.

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[tamathumper]

I believe it's a 29mm deep dish. Don't get the impact ones, as they are too thick to fit between the switch and the body of the car. Or, you can use a wrench too if you take the fans out, which is easy peasy.

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[flash]

correct. 29mm - you can get it at pep boys.



BE CAREFUL HOW TIGHT YOU CRANK DOWN ON THAT. THE TANK IS PLASTIC!!!

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[jthomson]

Thanks gang,

I'm pretty busy the next two weekends but should be able to get after iteventually. I'll keep you posted.

JT

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[flash]

fan operation is always in pairs.

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[DaveN]

Yeah, that's it, 29mm. And your right, I recall fussing with it as far as socket width and depth. Although the tank is plastic and you have to be careful I stuck my finger in the hole and my rad (replaced 5 years ago) has a metal threaded collar on the inside.

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[jthomson]

Flash,

That's what I thought. Clarks only has info on the 944. It seems that the driver's side fan kicks in by itself at first.



So...took it out for a spin today. No problems-still running a tad hotter (just above the 8 o'clock position) but still no low speed fans. Let it idle and watched the temp rise a bit. Turned on the air-low speed fans kicked on-it stopped rising. Revved the engine and it returned to 8 o'clock. Right where it was running last year. Looks like WP and thermostat are functioning. However according to Jamie'92's block diagram, if the AC and compressor are on, the high speed fans should kick in. My high speed doesn't hit until the gauge is at 10 o'clock. Think it's the temp switch for the fans?



Thanks as always. I'm learning sooo much!



jt

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[flash]

before you go yanking your fan switch:



make sure the big resistors on the firewall near the battery are working. those connections are known to go bad. it happened on my car.



make sure the fan control relay is not the culprit. find a buddy with a 968 and pop his in there and see if things start working again. i had this happen on mrmister's car.



as for AC and high or low, i continue to have a senior moment on that one, and always have to go check, but i could have sworn it ran on low, not high.

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[jthomson]

Flash,



On Jamie'92's diagram, he has AC running to the low speed and AC/compressor running to the high speed....so I'm a little confused. Jamie'92 could you clarify?

I think it makes sense that the low speed would come on. The high speed would only be for intense situations, right?



And I'd love to find a buddy with a 968, alas, I have the only one in Iowa...so lonely...



Also, how do I get replies to my thread to notify me in email? I've checked the tutorial and thought I had the correct settings in my profile but so far nada.



Thanks, jt

Also, too, where can I find the values of those resistors?

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[flash]

in your control panel, there is a whole list of things like that you can do.



the resistors are available and inexpensive. i would not try substituting something else in there. there is a test procedure here in the cooling system area.

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[jthomson]

OK, the latest.

Tested everything that was mentioned previously. All functioning properly, except low speed fans, of course. Took the car on vacation. 750 mile round trip to Door County, Wis. Also lots of touring while I was there.

No problems at all. At speed even in 85+ degrees, car stayed cool w/o fans. In town if the gauge started to climb, I turned on the a/c. No problems. Quite sure it's the temp switch. Will replace it and keep you all posted.

Saw the test section about checking the temp switch. I may try that if I'm feeling confident.

Btw, it's just one piece with the two resistors in it, correct?

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[flash]

the fan temp switch is in the radiator. the resistors are on the firewall.

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