On my '93 240, I replaced that o-ring for the heater tube without removing the water pump. There was a mounting tab on the tube with a small bolt holding the tube to the engine. Removing this bolt allowed me to pull the tube out of the water pump and replace the o-ring. Then I pushed the tube back into the pump and reinstalled the bolt. 'Didn't even have to touch the heater hose at the other end of the tube. Took about 10 minutes. Maybe the design changed on later models. That repair lasted for over 100 miles and was still good when we sold the car.

I do agree with your comments on the design of the pulley planes on the water pump. It's too tricky to lever that pump up against the top o-ring and too easy to overtighten the belt and damage the bearing, DAMHIK.

Most V block engines I've worked on have a pretty flat water pump whether Ford, GM, or others. However, I have nothing but scorn for Ford and their 3.8L v-6. The one I had was on its 3rd set of head gaskets by 90,000 miles! In researching this problem I found Ford had been selling this defective design for many years. They did the same with bad transmissions for that car as well as bad ignition modules and fuel pumps in their Escort models. GRRR!!! Get off that soap box!!!