Well, I guess I got my comeuppance today. I've changed the waterpump twice on my 1987 740 turbo, using no gasket seal, with no problem. Today, I spent 5 hours trying to replace the waterpump on my wife's 1993 940 Volvo. I scraped clean the mating surface on the cylinder head and did not use any gasket seal. Installed a new OEM Volvo waterpump. Got a good tight fit on the hat seal on top. Then, when I put in new antifreeze, it was leaking like a sieve! Leaking from the bolt threads and the bottom, through the gasket. Though the Haynes manual does not mention gasket seal, I'm betting the professionals use a thin layer of it.
Question 1: What brand gasket seal do you folks recommend? Is it flexible? Can it be used on the bolt threads?
Question 2: The Haynes manual does not give a torque specification for the waterpump bolts and nuts. I've misplaced my Bentley manual, due so spring cleaning. Anybody have those specs? (I do not want to break a stud. I've done that in my youth, and I don't want to repeat that!)
Thanks, guys.