For info...:
Following an earlier thread where someone reporting engine coolant temp needle running just above cold/blue bar (instead of level at the midpoint of gauge), I took the advice of one contributant and changed my thermostat with standard Saab 89C replacement (alternative 82C not suitable for Old Blighty temps!).
NB: My gauge had been running fairly consistently just above cold blue bar, since last summer - in most outside temps. Thermostat was the original on a 1998 2L Eco with 140k miles. On this basis - I recon life of thermostate must be around 130k mikes +/- something!
Checked old unit (no thermometer available) using v-hot/cooler water, and it opened/closed as would be expected!!
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But since running car, temp needle now runs at the mid/horizontal position (i.e. normal) even with outside tempreture at 1C on this mornings run, and never below twice the hight of the cold/blue bar.
Lesson - standard Wax Type thermostats age, and go out of calibration - running cool, instead of failing open or closed (as the old bellows type used to do.
So, if anyone has similar simptom, I can recommend a thermostat change. 1 hour if rushed - two hours if fairly lesurely and checking of hoses necessary, including drain and replaceing sufficient coolant to drop level below thermostate housing.
Draining Cololant Process
I drained coolant by taking return pipe off top off expansion tank, and placing end in a clean plastic milk bottle. Then connecting foot pump (air bed type - with long hose) to small lenght of clean petrol pipe. This was held against the small plastic tube now exposed on expansion tank. By pumping, pressure into expansion tank pushed out some 4 - 5 pints of coolant (emptying milk bottle into larger container once - or just have two milk bottles). As I had only changed coolant 2 months ago, with 3 year lifespan Comma Blue, this process enabled easy extraction and reuse with no loss!
Following an earlier thread where someone reporting engine coolant temp needle running just above cold/blue bar (instead of level at the midpoint of gauge), I took the advice of one contributant and changed my thermostat with standard Saab 89C replacement (alternative 82C not suitable for Old Blighty temps!).
NB: My gauge had been running fairly consistently just above cold blue bar, since last summer - in most outside temps. Thermostat was the original on a 1998 2L Eco with 140k miles. On this basis - I recon life of thermostate must be around 130k mikes +/- something!
Checked old unit (no thermometer available) using v-hot/cooler water, and it opened/closed as would be expected!!
But since running car, temp needle now runs at the mid/horizontal position (i.e. normal) even with outside tempreture at 1C on this mornings run, and never below twice the hight of the cold/blue bar.
Lesson - standard Wax Type thermostats age, and go out of calibration - running cool, instead of failing open or closed (as the old bellows type used to do.
So, if anyone has similar simptom, I can recommend a thermostat change. 1 hour if rushed - two hours if fairly lesurely and checking of hoses necessary, including drain and replaceing sufficient coolant to drop level below thermostate housing.
Draining Cololant Process
I drained coolant by taking return pipe off top off expansion tank, and placing end in a clean plastic milk bottle. Then connecting foot pump (air bed type - with long hose) to small lenght of clean petrol pipe. This was held against the small plastic tube now exposed on expansion tank. By pumping, pressure into expansion tank pushed out some 4 - 5 pints of coolant (emptying milk bottle into larger container once - or just have two milk bottles). As I had only changed coolant 2 months ago, with 3 year lifespan Comma Blue, this process enabled easy extraction and reuse with no loss!
