3 Attachment(s)
Thermostat Replacement - 900 Turbo
Tutorial for Saab 900 turbo thermostat replacement.
This is a fairly easy job. A bit cramped, but nothing major. I was done in about a hour and 20 minutes.
Tools:
13 mm open ended wrench
13 mm socket
12 mm socket (two of the bolts are supposedly 13 mm, but I found them to be 12 mm)
10 mm socket
7 mm socket (or if you prefer a flat head screwdriver to get off hose clamps)
socket wrench
flat head screwdriver
large catch pan (larger than 1ft in diameter)
Parts:
The only parts you need (assuming you are here to replace the thermostat) is a new thermostat. But, it would also be a good time to replace the throttle body coolant hose, heater core coolant hose and the upper radiator hose (the upper radiator is very easy to do, without this entire procedure, the others require the vast majority of this procedure to get good access to).
Time:
1hr 20 min for me. Maybe up to 2hr if you have no idea what you are doing.
Difficulty:
It's pretty easy. A bit tight, and if you drop a bolt, you'll have some fun fetching it. But nothing too hard. I'd say 1/5 or 2/5.
Directions:
The car used to make this is a 1996 900 SE turbo with automatic transmission.
Remove the plastic engine cover and set it aside.
The picture below points out all the bolts, electrical connections and hose clamps needed to be undone to remove the aluminum charge pipe. Bolts "A" are 10 mm bolts, electrical connections "B" can be undone with a screw driver by carefully prying out on the flat red piece, for bolt "C" use the open ended wrench (it may take some pushing on the charge pipe to be able to undo the bolt completely) and hose clamps "D" can be undone with a 7mm socket or a flat head screw driver. Now the charge pipe can be removed and set aside. Underneath this charge pipe is the upper radiator hose. You can completely remove it by undoing both hose clamps, or just undo the one that connects to the thermostat housing and push the hose to the side.
Attachment 10464
Circled above, and marked "E" are two brackets held onto the head by the same two 13 mm bolts. Use the open ended wrench and remove those and set the aluminum bracket to the side. The bracket with the electrical connections should be pushed back and out of the way, and may require undoing some of the connections (I had to undo the Lambda/O2 sensor).
You should be looking at this now, which is right below the area you've been working on, at the back right corner of the engine.
Attachment 10462
Place your catch pan underneath the transmission. Slightly closer to the back of the transmission than the front if your pan is small. Simply break bolts "F" free. Don't take them out, just make sure they'll come loose. You can get these with the 13 mm socket, but I found they were 12 mm for me. You might need a deep socket or an extension to get the lower bolt. The picture below is meant to show you where the lower bolt "F" is, as it's hard to see exactly where it is. This is the thermostat housing and the thermostat resides inside.
Attachment 10463
Got that catch pan in place? Good. Undo hose clamp "G", which is located on throttle body hose, with a flat head or a 7 mm socket. When you undo this and remove the hose you'll get about a gallon or so of coolant coming out. It will run all over your transmission and is a mess, but a majority should be caught by the pan. (Notice I took these pictures when I was putting back together, with all the coolant still puddled on top of the transmission).
Remove bolts "H" with a 10 mm socket. Now go back and fully remove bolts "F". The housing should now be free. It might need a bit of coaxing, but mine came off easy. So pull it off and set it aside. Remove the thermostat as well, and make sure that the gasket comes with it too. The thermostat might be stuck. Mine was. Whatever you do, do not pry against the flat surface that the thermostat housing mounts to. You want it nice, flat, and clean so you'll get a good seal.
Put the new thermostat in and make sure the the small valve on it is at the top when you put it in. Why? I dunno.
Now just put it all back together reverse of how you took it apart. Once it's all back together, fill it up with coolant. With the coolant expansion reservoir still open (cap off), turn on the car, and keep topping it off. It will eventually equalize; once it does, put the cap back on. Drive it around the block and let the engine get fully warm and make sure your heat works. Now, carefully top it off again if needed once it cools down. You might have to keep topping it off for the next couple of drives as air keeps working its way out.
