Today, when I drove about 30 kilometers, I stopped an let the engine run on idle. I could se the temp slowly move towards the red. I continued to drive when the temp was on the line between the red and green. What can this be? Is my water-pump bad?
I had a fan problem on my old 9000CS, fan didn’t kick in when it should. Checked the fuse, coolant level, thermo-switch and they were all fine. Checked the supply to the relay, no voltage, so I assumed there was a break in the supply wire to the relay, nightmare of a job if you wanted to do it properly. The supply to the relay is permanent (not through the ignition, otherwise it wouldn’t run after turning the engine off). I settled for a new 12v supply from the battery to the relay, with an inline fuse of course.
The fan did not start, but it did something strange when I started the car cold. I started the car and after a minute or two, the fan started and ran for about 5 seconds. Then it stopped and the car ran for about 3-4 minutes and the fan started again and ran for about 5 seconds. Is this something normal? I know that the car runs hotter when idling, but when should the fan kick in? Before the temp reaches the red?
Sounds like an electrical fault, if the fan is turning itself on and off whether the engine is hot or not would suggest the fan switch or the relay is dodgy. A quick test to see if the switch is broken and the rest of the fan circuit is working is to bridge the contacts of the fan switch with a screwdriver, if the fan runs normally the circuit is fine and the switch may be broken. Keep your hands well away from the fan when you do this check!!
If it still doesn't work. Use a multimeter to see if there's a voltage across the switch, if not check the earth connection to the switch is good.
One other thing, if your car has air con, then turning it on should also turn on the cooling fan. This will let you know that the fan / relay is working.
I had the same problem on my '94 9000 CSE, well almost. My fan used to kick in just little below the red. A wire from the relay had corroded and needed to be replaced. Apparently it common on a car of this age, a saab tech should know about it and how to fix it.
Sorry cant help more as not sure exactly which wire he replaced when he did mine. I know it was something in the low speed cooling fan circuit as the high speed one worked fine.
assuming your car has climate control, the fan is turned on by two things; 1) coolant temperature 2) the climate control system pressure. It is common for the wiring in one of these circuits to fail.
If the fan comes on within a few minutes of a cold start, but only runs for a few seconds, it is being turned on by the climate control. If it is turned on by the coolant temperature, then the gauge will show near, but not yet in, the red zone, and the fan will runs for 45 seconds or more.
I suspect that you have a failure in the coolant switched wiring loom.