[xrad]

can't find the post, but someone (Flash?) mentioned putting in an aftermarket fan temp switch into the radiator.



My fans kick on (according to the tick mark conversion on my temp guage) at just under 100C(212f). they turn off at just over 80C(~180)



is this correct? temp needle goes almost to the 100C tick mark. I would like them to come on at about 92-95C. I was considering an aftermarket temp control but maybe you guys hav another idea....



When on the road, new radiator and T-stat work perfectly keeping the car just hovering over the 80C tick mark.

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[flash]

the low speed fan should come on about where yours go off - the high speed fan should come on where yours are coming on



sounds like a bad fan switch, fan, or fan relay or fuse, if you only get one speed



take a look to see that you have both fans spinning - also, engage the ac to see if the speed changes



report back and we can nail this down

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[xrad]

thanks! will check!

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[94SilverCab]

RS Barn reports initial sign of fan motor dying is fuse blowing..my fuse has blown and now I'm waiting for the inevitable.



Jay

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[xrad]

fuses OK (25's)



BOTH fans turn on at ~100C. and both turn off as I stated above. Also, BOTH fans turn on when engine cool and AC button pressed. fans turn nice a smoothly by hand. all wiring looks clean.





Relay? maybe...maybe not . I don't have a spare one of these to test. Seems like a temp switch problem....I am pretty sure I pulled the old one out of the old radiator and put it into the new radiator.







ALSO: in my never ending search for vac leaks, I found another one today. right above the driver side engine mount there is a vac line going into the intake manifold. I just touched it and the metal tube fell out. Still attached to the hose. I widened the tube just a hair and added some silicone sealant and it went in nice and snug. Ran two zip ties through the manifold support which then pull the hose clamp and the fitting closer to the manifold. Not going anywhere...and I am pretty sure there is no leak.



It seems that with each leak I fix, my car gains at least 5HP...wow..could be in my head, too.

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[flash]

so you only have one speed of fan, and it is the same with and without AC?



that tells me you have either a bad fan switch, the wrong fan switch (a 944 single speed rather than the 968 2 speed), or a bad relay, but i would have to look at the diagram to see if the relays are one for each fan, or one for each speed

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[Cloud9...68]

It's been so long since my car has been running that my memory may be faulty, but I remember the PO telling me he had installed a low temp fan switch in my car, and I'm pretty sure BOTH fans come on right at the 8:00 oclock mark, which corresponds to 176 deg F. Seeing as I live in a warm climate, this has never seemed to be a problem. Until late last year, my gauge seldom got above the 8:00 oclock line, probably because the fans blow up such a storm at that point.



But what puzzles me is that I now I have a standard 190 degree thermostat (which I installed when I did my belts, seals, rollers, and water pump this past March), which means that, theoretically, it should never have opened, because my gauge almost never indicated the equivalent of 190 deg F. So, the iterplay between the thermostat temp at the fan switch temp seems to be very important. Is it possible that my whole problem (sorry, I guess I should be posting this on my own thread about my car's hot running problem, but I kind of feel like I may be having an aha! moment here, so I'm getting a little excited...) is that when the PO installed the low temp fan switch, he also (correctly) installed a low temp thermostat? Now that I have a low temp fan switch, but a "high" temp thermostat, the fans are keeping the water in the radiator too cool to get the thermostat to open? Given the direction of flow, this seems to make sense. Thoughts?

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[xrad]

the piece that controls opening of the thermostat is located on the engine side so that it sits in the engine flow of hot water(makes sense). unless thermostat is in backwards or not working, it should open at the specified temp. of course, your fans should kick right on when this Hot water hits the temp control...



Flash: i will test the switch. relay has an aluminum cover with no labels. it is a one piece design with two internal relays

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[xrad]

Bought a new radiator switch and fan relay. will test when they arrive.

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[xrad]

received the new relay. Fans turn on at same time at same temp. Will try the radiator switch when it comes.



Went for a 100 mile drive today. ran great. Front end follows grooved concrete, but otherwise no problems. Of course, temp golden the entire time I was moving. Only rises when stopped.

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[earossi]

[quote name='xrad' post='55803' date='Jul 4 2008, 11:48 AM']received the new relay. Fans turn on at same time at same temp. Will try the radiator switch when it comes.



Went for a 100 mile drive today. ran great. Front end follows grooved concrete, but otherwise no problems. Of course, temp golden the entire time I was moving. Only rises when stopped.[/quote]





The front end of your car following grooves in the road is most likely due to the tires on the car. I used to have that issue with one of my 911's that had Bridgestones mounted. When the tires wore out I replaced them with Michelins and the problem went away.



On thing that you may want to try with your overheating problem is to add a product called "Water Wetter". It apparently lowers the surface tension of water allowing for better heat transfer. Someone on this board mentioned useing it successfully a year or so ago.



Please post your solution when you finally run it down. A lot of members have had similar problems and not posted their "cure".

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[flash]

yes and yes - i have the same bridgestone issue and the water wetter did indeed have the indicated affect

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[PorscheDude]

My car tramlines with 225/40/18 Michelins and recent castor blocks only on the worst of roads.

As a side note I have somewhat of an aggressive street alignment.

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[xrad]

just got the thermoswitch. will install this weekend.

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[unknown4u]

I'm interested about the results. If the temp stays at the 8 oçlock mark.

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[RS Barn]

You can test both fan circuits prior to installing thermos switch. just pull three prong connector and make a jumper. Jumper from brown to either other opening. One will be low speed and one will be high speed if all fine

Pete

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[unknown4u]

I shall test it, because sometimes in heavy traffic it forgot to swith into the first stage.

and than it works again for weeks



Good tip Pete!.

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[Cloud9...68]

[quote name='RS Barn' timestamp='1215564471' post='56009']

You can test both fan circuits prior to installing thermos switch. just pull three prong connector and make a jumper. Jumper from brown to either other opening. One will be low speed and one will be high speed if all fine

Pete

[/quote]

Could somebody please describe the three prong connector Pete is referring to, and where it's located? Thanks.

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[JWahlsten]

The prongs are on the fan switch at the radiator. Driver's side toward the top.

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[Cloud9...68]

Thanks, Joel. I'll check the operation of my fans tonight. I know at least the low speed function is working - I'd like to confirm the high speed is as well. My understanding is that the fans go into high speed mode when the AC is turned on. Is this correct? If so, another way to test the high speed function would be to run the car (I would run it long enough for the fans to start running at low speed), then have an assistant press the AC switch while I watch for the fans to speed up. Is this correct?

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