Saabscene Saab Forum - Saab Technical Information Resource banner
1 - 6 of 6 Posts

·
Registered
Joined
·
1,908 Posts
Discussion Starter · #1 ·
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!!


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!
 

·
Registered
Joined
·
222 Posts
Mine has recently started doing this (running lower than before), two questions:

Is it actually detrimental for the engine for it to just carry on working like this (it sits around 8 o'clock when running and the fan now kicks in at 10 o'clock rather than nearly in the red as it used to) ?

How much does a new one cost and where do you get them from ?
 

·
Registered
Joined
·
2,928 Posts
If the fan starts at a different place on the temp gauge, I'm tempted to suggest that there's some extra resistance in the temperature gauge circuit (dirty/corroded connector at the sensor?) causing the gauge to read cooler than reality.
 

·
Registered
Joined
·
1,908 Posts
Discussion Starter · #5 ·
I wouldn't say running slightly cool was detrimental to the engine, and agree it will drop fuel consumption - plus increase your emissions somewhat. Also, on very cold days, the cabin tempreture will take longer to reach set temp and might not even reach 21 - 22C if motorway cruising, etc.

Fan kicking in at lower temp would not be related to a faulty thermostat - more a fan/connector fault as suggested.

Cost of new 89C thermostat (Saab part) was about £5 plus £1 postage. Elkparts can source these.
 
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top