9-5 Aero; Coolant sensor
Discussion
Funnily enough, I just bought my wife the same car and looking at the dip stick it looked like the dreaded head gasket mayonnaise but was convinced that it was due to the shape of dipstick collecting moisture.
Fast forward to Wednesday and the CEL lit up, just as the OPs, and having checked the dipstick which looked considerably worse I convinced myself the head gasket had gone despite no issues with the coolant (bubbling etc). The garage rang me up today telling me there was no problem with the head gasket and the CEL fault code was the coolant sensor but they were unable to find anyhing wrong with it, so had simply reset it.
Possibly an issue related to the recent cold temperatures?
Fast forward to Wednesday and the CEL lit up, just as the OPs, and having checked the dipstick which looked considerably worse I convinced myself the head gasket had gone despite no issues with the coolant (bubbling etc). The garage rang me up today telling me there was no problem with the head gasket and the CEL fault code was the coolant sensor but they were unable to find anyhing wrong with it, so had simply reset it.
Possibly an issue related to the recent cold temperatures?
paul makin said:
when the ecu interrogates the sensor it requires a response within 3 seconds - if no response (failed sensor),CEL will be triggered
if the ECU receives an improbable value it'll chuck a CEL, eg failed stat causing cool running despite time elapsed from start-up.
Thanks chap.if the ECU receives an improbable value it'll chuck a CEL, eg failed stat causing cool running despite time elapsed from start-up.
Coolant sensor replaced (and car serviced). Temp gauge worked day 1.
Day 2, temp worked on the way to the zoo, dropped to zero on the way back. No CEL. Heaters blowing hot air.
Day 3, worked again.
Under observation.
I have a similar problem with my '02 9-5 aero. Temp gauge reading "zero", but no CEL light. Heaters working OK. It only seems to happen around this time of year.
Looking at the other Saab forums, it's likely a faulty thermostat causing it:
http://www.saablink.net/forum/car-problems-9-5-onl...
I guess the thermostat is sticking open, so the engine doesn't reach temperature as quickly as it should.
Looking at the other Saab forums, it's likely a faulty thermostat causing it:
http://www.saablink.net/forum/car-problems-9-5-onl...
I guess the thermostat is sticking open, so the engine doesn't reach temperature as quickly as it should.
groomi said:
II did catch temp gauge at zero yesterday morning after a half hour drive - no warning light though. Been reading fine since.
Yup. Dropped to zero once with no cel. Been fine ever since. Still keeping my eyes on it.In other news, heated seats proving more useful than I imagined this time of year and traction 'interesting' with all this water.
bint said:
Car in garage again for the sensor and engine mount knocking 
sensor wire was loose, sorted, mount not off the shelf in the uk, do awaiting delivery from Sweden.
Just as well it's snowy and I don't need to drive anywhere....
Is this with a main dealer? Partsforsaabs have aftermarket ones in stock. As you say, in the snow it's best left at home as mine is hopeless on wide summer tyres! sensor wire was loose, sorted, mount not off the shelf in the uk, do awaiting delivery from Sweden. Just as well it's snowy and I don't need to drive anywhere....
Had exactly this but no CEL light. Booting it home along a back road on a chilly night, gauge just dropped like a stone and was a bit twitchy the following day. Replacement sensor and thermostat £20 from Saab dealer. Mechanic across the road fitted them for £30. Everything cushti 2 weeks later.
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