Hello Just changed my thermostat. Volvospeed procedure very helpful.

http://volvospeed.com/Repair/thermect.htm

I want to add my own tips:

1. Per Volvospeed, Yes the 7-inch 40 torx screwdriver is a must. I bought mine at Autozone in Chicago. It comes as a whole set of Torx (similar to Hex key set) with different sizes for $17.00.

2. I used the 87-deg-celsius (instead of 90-deg-C) thermostat @ FCP Gorotn http://www.foreigncarpartsonline.com/

This allows the car to run a bit cooler. Just my style. If you tell me this may make the engine runs rich, then I have my answer...The Bosch Motronic Electronic computer is programmed in such a way that as temp rises above 60-deg-C the mixture is optimized, i.e., no difference in fuel/air mixture between 60-deg and 90deg.

3. Use a magnet (telescope) to re-install the inner screw, it is a tight space so this magnet helps in guiding the screw in place (if you have small hand then it is not a problem).

4. Apply small amount of wheel-bearing grease at the tips of the screws to avoid corrosion and allows easy removal in the future (if you keep the car that long).

5. The procedure at Volvospeed calls for disconnecting the overflow hose the thermostat housing. I disconnect the overflow hose where it attaches the collant reservoir because this is easier. Also in my car Volvo uses a quick clamp (snap-on) there. So a screw-type clamp in my mind is better. (I guess margin of profit is an issue for Volvo so they used many quick clamps in the car, it takes the assembly worker only 2 seconds per clamp instead of 1 minute if screw-type clamp is used).

6. Remember to point the hole in the thermostat forward at THE HIGHEST POINT OF THE HOUSING.

Hope this helps.

CN
1998 V70 55K MILES