Engine not up to temperature

[trwilson70]

Recent acquired 2003 9-5 - noticed that engine seemed to run cool according to gauge, I expected the needle to be at 9:00 position. When coasting down a hill the temp would fall. Finally got a CEL - checking with OBD-II found a P0116 - engine temp circuit - made sense. Ordered new thermostat, temp sensor, and red antifreeze from eeuroparts - installed last night. Thanks for the tutorials - instructions always make the job easier! Made a trip 15 miles north today with a long downhill stretch - the temp gauge dropped all the way down to the L! Any ideas what to check next - how to get the temp stabilized? I kept the old thermostat - I expected to find it stuck open - may bring it in the house and test on the stove. Thanks

[SaabScott]

Sorry. You seem to have the bases covered here.
Not sure what else to suggest.

[nordwulf]

Did you get another P0116 code when it dropped? I had the code on mine but without a CEL.

Did you get the Saab thermostat with the vent hole? I first went to my local parts store and got an after-market thermostat without the hole for $12. eEuroparts sells a Saab ($24.50) and a Wahler ($16.90) thermostat. I don't know how important this vent hole is so I ordered the genuine Saab thermostat just to be sure. Perhaps you have some air trapped in the system?

After I replaced the thermostat and temp sensor, coolant level was fine after a 200 mile drive. But it sat at an airport for 10 days and coolant (Dexcool - orange) had to be added after that.

[trwilson70]

I didn't check for a code - will do that this morning - no CEL. I got the Wahler thermostat - it does have a vent hole. I will watch the coolant level the next few days. On the level, or small hills the temp seems OK, but does fluctuate some. I will also test my old thermostat - just for fun. Thanks

[trwilson70]

Just checked - did not get another code from yesterdays adventure.

[jlrSAAB]

check the terminals in temperature sensor for a good contact and the wiring harness wires (the same color) terminals to the control unit engine.

maybe a failure contact in terminals.

[trwilson70]

Update - checked the wiring, appeared OK. Have been watching the coolant level and perhaps there was an air bubble. Have added a bit on several occasions and now temp seems to have stabilized.

[js8vv8]

I am planning on replacing the thermostat and temp. sending unit on my 9-5 3.0t soon. However, "the Saab Site" sent me the wrong parts, so that is on hold. My issue is on the freeway or very cold days, it shows all the way down on L for the temp gauge. I assume the thermostat is stuck open. After reading this thread I wonder if there is air trapped in the system. I did remove and clean out the coolant tank when I got the car because the prior owner had a used engine put in it and they didn't clean the tank out, (was a headgasket failure on orig. engine). I cleaned it out so would be easier to know if I had something going wrong with the headgasket on this replacement engine. so, when I did the cleaning it is possible I introduced some air into the system. However, that was about 3 weeks ago.

Should the cooling system have bled out any air by now?

I have driven the car many times, but most of my trips are less then a 1/2 hour drive. I have opened the coolant tank a couple of times and it did have pressure when I opened the orange fill cap and the coolant level has remained the same.

Thanks for any help from a Saab newbie