Porsche Enthusiasts Club Forum

Just after some advice to put my mind at ease.
Thought i would take advantage of the sun and lack of work today and had a run out in my 964.Dosnt normally happen but the temperature guage needle went up past the first mark on the guage to a horizontal position and even went to the last mark befor the red at times. I was stopping and starting in trafic some of the time. Just wanted to know if this was anything to worry about or if this was normal? Any advice would be appreciated.

In mega heat stuck in trafik i think mine has allso got to the 3/4 mark once, normally stops around half way in trafik. Did the fans on the oil coolers kick in?
Dont worry bout it, IMO.

First (and easy) thing to check is that your thermostat is opening. You can tell by touching your right front wheel arch/bumper when the engine is warm. It should be hot, and if your car's temperature gauge is around the "10 o'clock" mark, your right front wheel arch/bumper should be VERY hot. If it is no hotter than, say, your hood, then your thermostat is not opening allowing oil to flow up to the oil cooler.
You can then check the oil cooling fan; this should come on when the temp is a little above the "9 o'clock" mark. You'll be able to tell if it's on so by leaving the car idling and putting your hand in front of the right front wheel, inside the wheel arch. You should feel the breeze from the fan, which sends hot air into the wheel arch, and you should be able to hear the fan running.

Keep us posted.

PS There is a great troubleshooting guide over at p-car. The link is http://p-car.com/diy/fan/

Been trying to find the cause of my 964 overheating today.It would seem that the fan isnt cutting in at all so i first checked the fuse which was ok.Then i checked the ballast resistor by jumping the terminals and the fan worked in slow and fast speed so that seems to be working also. I replaced the thermostat and relay a couple of months ago so i tried the old thermostat back in with the new relay and the old relay back in with the new thermostat and so on but the fan still would not cut in even when the needle was at 10 o'clock.I was going to order a new relay in case the old and new relay i have are both faulty but its £40 quid so i think i might see if an auto electritian can test the relay and wiring first unless any one can think of owt i might be missing?

ps will put some pics on soon, she's hot! ha ha.

Had another look at sorting my 964 oil cooler fan today,fitted another new relay to no affect,also removed and heated the oil temp sensor then refitted it, the fan started at full speed then went to slow speed then stopped as the sensor cooled, everything seems to be working.
went out for a run in the car tonight to get it up to normal running temp, then let the car idle on my drive for about 10 to 15 mins the temp guage got to 10'oclock but the fan didnt cut in.
Going to keep an eye on it over the next few weeks, maybe it just isnt getting hot enough for the fan to start?

Some more technical data:

At approx 87°C (just before the 9 o'clock mark) the oil cooler thermostat opens - your front right hand bumper becomes warm.
At approx 105 °C (half-way between the 9 o'clock and the 10 o'clock marks) the control unit starts the oil cooler fan.
At approx 115 °C (the 10 o'clock mark) the oil cooler fan switches to fast speed.

So if you hit the 10 o'clock mark and the fan did not cut in, something seems to be amiss.

You can check that your ballast resistor is working properly by following the process described in the p-car page (link in a previous post).
Usual disclaimers, only do this if you feel competent etc.
Briefly:
-Remove relay R04 (oil cooler blower).
-Jump terminals 3(30) and 7(87c) for slow speed. Fan should run, even with the ignition off. Your ballast resistor is OK.

(Ref:- various posts in Rennlist and p-car site)

Cheers, i tested the resistor as described in the link and it worked perfectly.Everything i've tested works,only thing i can think of is the temp sensor. I tested it by running a current through it with a bulb wired in and heating it up over a flame till the bulb went on. Had to heat it up pritty hot befor the bulb lit up. Not sure if these temp sensors either work or dont work or wether they can become less sensitive if there faulty. I think i will get another one, so will let you know if it works.