If the thermostat hasn't been replaced in a long time, do that at the same time.

To prevent coolant spilling, drain about 1 quart of coolant from the engine drain plug or carefully loosen the lower coolant hose from the engine side and drain 1 quart or so. Remember to replace the clamp and hose in the same position as they were in before and do not overtighten the clamp.

If you replace the thermostat, there are 2 stubborn T40 bolts holding down the cover. Buy a good quality T40 driver with a 4" extension to your ratchet. Press down very hard to "break" the bolt loose, the heads are easy to strip and if you do strip them it can be a nightmare. If one bolt head strips, I suggest tightening the other back down and having a mechanic help you out.

The ECT is quite simple to replace, but clean the plug before you plug it back into the ECT. A dab if di-electric grease is always helpful to keep any moisture out.

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

Klaus
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Volvoless. Sold the R. There is now a void...