Temperature gauge

Hi, I'd appreciate any advice on the following problem which has recently come up on my 1998 9-5 saloon SE eco-urbo 2.3ltr. 91k miles. After only a few minutes driving the temperature gauge steadily rises to just over half-way whereupon the radiator fan kicks in. The temperature gauge then rises or falls slightly (to about three-quarters max, never goes into the red) but never dips below half-way. After parking the fan continues for 5 - 10 minutes before stopping by itself, with the ignition key out or in, makes no difference. This happens daily now on even only a five minute journey. The car has never behaved in this way before (had it for 5 years now) and normally drives with the temperature gauge holding steady at just over one-third of the way up. Even motorway driving does not even take it fully up to half-way. Normally I'd perhaps put it down to the hot weather, only it has been nothing exceptional and the car did not behave in this way during the extremely warm spell in the Spring. Nothing immediately obvious. Oil and coolant levels are ok, no obvious leaks other than the usual dribbles with a car of this age. Hoses ok. Serviced regularly. Driven carefully. No oil foam in the filler cap. Nothing on the garage floor over night. A local garage mechanic today came away scratching his head wanting to do a 'pressure test' for about £40. I can't afford to take it into local Saab dealership on spec in case I get stuffed. Any advice or diagnosis greatly appreciated from anyone who has experienced this before. Thanks.

Reply to
John Bain
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I think you need a thermostat. It's possible you need other work but the lack of coolant loss leads me to believe it's not a serious issue. You may also need some work on the fan, but start with a new thermostat and see how it does.

Reply to
still me

Hmm. Now I don't know for sure, but, would the cooling fans be ECU-controlled? The ECU knows the temperature by the coolant temperature sensor. If the sensor is duff, the ECU will be telling the dashboard that it's overheating and running the fan(s). Thus it may be something as simple as a temperature sensor.

Reply to
DervMan

In message , John Bain writes

First thought is your thermostat needs replacing, less than 20 quid in parts including new coolant. The temperature gauge on the 9-5 is controlled by the ECU so if all is well with the car it should sit bang on 9 o'clock and never deviate whatever you are doing, if the thermostat is sticking part closed so coolant isn't properly circulating around the radiator then the fan will kick in - don't worry about the fan running after you shut the car down, it is supposed to do that to cool the system down.

Andy

Reply to
Andrew Sinclair

He mentioned running cool on the highway, I think that means he needs a thermostat no matter what.

Reply to
still me

thanks to everyone who has helped with their advice. much appreciated. Perhaps I should clarify that previously - ie before this problem started - the car would hold temperature at somewhere between one third and half-way up on the temperature gauge no matter what. even on a run of up to one hour at moderate speed, including motorway driving, there would be no instance of the temperature gauge even approaching half way up and during my ownership the fan has almost never cut in after the car has stopped moving unless the weather has been extremely hot. The fan is now cutting in while the car is still driving even after only around five minutes of driving and the temperature gauge rises steadily during the same time to between half-way and three-quarters up and goes up or down only very slightly once it has reached this position. My fear is that on a longer run if I lose the fan for any reason the engine will seriously overheat as I think the fan is keeping the temperature in check. From what I am learning, I think the problem is the coolant is not circulating as it should from start up and this could be due to the thermostat failing. I am planning to replace the thermostat in the next day or two. If there might be any other possibility for the source of the problem I'd again appreciate the group's thoughts. Thanks again.

"Andrew Sinclair" wrote in message news: snipped-for-privacy@smellycat.org...

Reply to
John Bain

Possibly - but you can adjust the 9-3's coolant temperature gauge using the Tech2 instrument.

Reply to
DervMan

again

Reply to
DervMan

When driving at highway speeds, like on your "motorway" the fan does very little. The majority of cooling is via the air forced through the radiator from the forward travel. The fan is primariuly there for when you are stopped and the coolant in the radiator is too hot to cool the engine. So, I would not be that concerned about the fan causing problems in the middle of a trip. More like at the end, or in city traffic.

But I must tell you that I have owned a lot of SAABs and they all have kicked the electric fan on as you describe. When you stop the car and the sensor sees the coolant temperature is high the fan will continue to run. This happens even in cool weather.

Also be aware that any time the Air Conditioning is running the fan will be turned on. So if you have the ACC set to auto and the cabin temps get high it will engage the AC compressor and also the electric cooling fan.

Reply to
Fred W

For normal driving it shouldn't be a problem as the constant air flow through the radiator and over the engine itself will do most or all of the cooling. If you are driving the car hard and fast, or slow in stop/start suburban traffic, then you might find the temp gauge goes up more than normal.

1/2 to 3/4 isn't generally a problem, but if it goes higher and stays there for an extended period, it could be a circulation issue, or perhaps the thermostat isn't working.

Craig.

-- Mr Saab_o_Naut's backup login account!

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Reply to
Craig Ian Dewick

Hi all, I had the thermostat (and coolant) replaced by local saab dealer. The temperature gauge is now sitting bang on half-way up and doesn't budge. The only thing is that it reaches there just as quickly as it did before when i noticed the problem - ie within a few minutes of driving. Before that it took a lot longer to even reach one third the way up. However, on stopping now after a short journey the fan isn't already on and/or comes on like it did. Hopefully that is it although I can't help feeling it shouldn't be warming up as quickly as it is doing. Maybe there is still a sensor problem? Saab have assured me it is ok now. But I have been 'assured' before. Thanks anyway to everyone who advised. regards jb

Reply to
John Bain

Hi,

Please see below ...

John Ba> Hi all,

Good. The job of the thermostat is to stay shut until the car reaches the right temperature.

Well, in practice once it reaches the right temperature it opens slowly where the hot coolant mixes with cold and it goes colder again and closes a bit and so on ... if you had an accurate way of seeing the temperature ... it would rise and fall until it became reasonably stable.

Before that it took a lot longer to even

It was probably stuck a bit open, so it took longer to warm up but not open enough for when the car reached operating temperature to cool it down(?). The sensor for the fan ought to be on the cool side of the thermostat (am I right/wrong? is it on this car?) .... so it should not be affected by a sticky thermostat.

I think it should be (there again what do I know). It should warm up as quickly as possible. Ideally you want it to be warmed up before you started the engine.

Drive the car. If you have a hot day and with the engine just idling the fan should start! If it does not then back to dealer.

Please make an effort to space your text properly. You seem to be pressing Carriage return (enter) at the end of every line but you do not form paragraphs (i.e. double carriage return).

I tried twice to answer your message below but I found difficult to follow what exactly was the problem. What you see is how I see it (saw it).

:-) Take care Charles

Reply to
Charles C.

Don't worry about the fan or the speed at which it warms up. It sounds like it's fine. Your only worry should be if it does not reach the halfway point in a reasonable time or if it starts to run over halfway on a hot day.

One way to "test" the fan, if you are worried, is to let the car idle in the driveway for 20-30 minutes. You will hear the fan come on and off. As long as the temp gauge stays at the halfway point, the car is fine.

Reply to
still me

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