Saab 9-5 thermostat replacement - 4-cyl petrol/gasoline engine

[SaabWorld]

Warning
Take care if the car is warm. The coolant is hot and there is also a risk of burning yourself on the exhaust manifold.

To remove



1. Open the cap on the expansion tank and release the pressure.

2. Raise the car.

3. Remove the lower front cover.

4. Drain off the coolant.

5. Lower the car to the floor.

6. Loosen the hose clamp on the upper radiator hose mounting at the thermostat housing.



7. Move the hose to one side.

8. Undo the ground connection and bracket for the coolant pipe by the thermostat
housing.



9. Slacken the upper bolt for the thermostat housing and remove the lower bolt.

10. Remove the thermostat housing and thermostat.



To fit



1. Check and clean the sealing surfaces. Grease the rubber seal lightly with non-acidic vaseline.

2. When fitting the thermostat, ensure that the vent hole is at the top (thermostat
marking ”TOP”).

3. Fit the thermostat housing.



Tightening torque: 22 Nm (16.2 lbf ft).

4. Fit the ground cable and the coolant pipe bracket. Apply acid-free vaseline to both sides of the ground connection.

5. Position the upper radiator hose and fit the hose clip on it. Connect the radiator hose.



6. Fill with coolant. Do not forget to close the drain plug on the radiator first. Refer to Coolant for mixtures. Close the cap.

7. Check for coolant leakage. Start the engine, set the heat to max. and run the engine until warm.

8. Switch off the engine.

9. Check the coolant level.

10. Raise the car.

11. Fit the lower front cover.

[nordwulf]

Tools needed
Ratchet, extension, metric sockets 10 and 13 mm, screw driver, torx bits, car ramps or axle stands. Hose clamp pliers are not necessary but make it very easy to handle hose clamps. Basic pliers should work as well. 19mm wrench shown is only needed to replace the coolant temperature sensor (not part of this tutorial).



Supplies needed
Thermostat with rubber gasket. Saab part no 30577561



Difficulty rating
2 (scale 1 to 5). It is one of those jobs that seems easy in theory but much more time consuming than expected. There is little space to work at the back of the engine with a lot of wires and hoses in the way.

Time estimate
1 - 2 hours if you have done this before. 2 - 3 hours if this is the first time.

This is not a complete tutorial but more of an addition to the instructions from the WIS in the previous post.

The large black intake pipe is pretty much in the way and makes it difficult to see what you're doing. I decided to disconnect the pipe from the throttle body and move it out of the way to have easier access.







Drain about 1 gallon / 3-4 liters of coolant. The green petcock is difficult to access and open. I ended up using a screwdriver to push on one side of the petcock and one finger to pull to get this green valve to turn and open. Other tutorials describe to access from the top of the engine bay but there was no way I could get my hand/arm in that narrow space.

The petcock opens counter-clockwise. Turn 1/4 and pull out. Be careful not to break anything because it's mostly plastic. I cut the top of a milk/water gallon jug to catch the coolant when it drained. The coolant looked very clean so I decided to re-use.



I wasn't able to remove the coolant hose from the thermostat housing so I removed from the radiator.



The thermostat housing is held in place with two 13mm and two 10mm bolts. When you install the new thermostat, make sure the vent hole is on top. It is difficult to see the housing bolts and you don't have a lot of room to turn the ratchet. Here you can see why you need the long extension. Patience and small hands will be a nice advantage as well.

[Niknaks]

Fantastic writeup! Thanks.
I did the thermostat and sensor in about an hour. Not hard to do.
The water was clean and I found no deposits!!
I also had the classic symptoms with the temp gage just going down and also , it took a long time for the temp to come up.
Old thermostat was always slightly open.
I think that I have found the reason why it was not working as well.

On the old thermostat it says "Made in England"!

Thank you again, this has saved me a pile of moola!

[solander]

Thanks for the info Frank, another job done with your excellent assistance. When I pulled the old thermostat, it wasn't fully closed. With the new unit installed, my 9.5 heats up really quickly, cabin heat is there by the time I reach the end of the house driveway and the temperature gauge is rock steady, right in the middle of the range. Now, time to find that transmission oil leak !!.

[walawala]

I recently changed both thermostat and the thermostatic switch. Have a symptom where the car would start and idle rough and die when hot. Since I've changed CPS and fixed all vacuum leaks I'd thought I would tackle these since I doubt the previous owner ever changed them.

The thermostat was also halfway open, and the rubber seal was starting to disintegrate. Car warms up alot quicker and fan doesn't come on every morning once the car is started.

But I still have the difficulty of the car starting when hot. Time to do another round of Throttle Body cleaning?

des

P.S: on right hand cars we're lucky. Thermostat is a real easy change as the brake fluid reservoir is on the other side.

[Breau]

I recently changed both thermostat and the thermostatic switch. Have a symptom where the car would start and idle rough and die when hot. Since I've changed CPS and fixed all vacuum leaks I'd thought I would tackle these since I doubt the previous owner ever changed them.

The thermostat was also halfway open, and the rubber seal was starting to disintegrate. Car warms up alot quicker and fan doesn't come on every morning once the car is started.

But I still have the difficulty of the car starting when hot. Time to do another round of Throttle Body cleaning?

des

P.S: on right hand cars we're lucky. Thermostat is a real easy change as the brake fluid reservoir is on the other side.

Do you have to wait for it to start up when warm or is there just hesitation when starting? If you have to wait it is most likely the Neutral Safety Switch.

[walawala]

Do you have to wait for it to start up when warm or is there just hesitation when starting? If you have to wait it is most likely the Neutral Safety Switch.

Nope, it just starts the idles rough and dies. Think I got it fixed , was a broken check valve towards the mechanical pump. So far car starts fine now.

[rock30459]

Hello to all.. my problem is the one where you're driving along all happy and stuff and your gauge suddenly goes all the way down and the [check engine] icon shows then when you restart the guage goes up but icon stays lit--so thermostat right?...the car is going in for 54,000 or is it 55,000 mi service any day [when i can find someone that knows saabs that is]. I have huge hands and too much stress already to fix it myself.. My question is can it be driven safely as in no engine damage.. When I find someone reputable I will most likely have to drive it a ways. Thanks

[nordwulf]

My question is can it be driven safely as in no engine damage.. When I find someone reputable I will most likely have to drive it a ways. Thanks

Yes, that's the thermostat going bad. The coolant temperature sensor is often changed at the same time but may not be necessary. It won't cause any damage to the engine when you drive it like this for a while.

I have medium-sized hands and it was difficult for me to get in those hard-to-reach places with tools. It'll be well worth it to pay someone else to do this.

[rock30459]

OK Frank-Thanks very much..