Amazonphil's and Allrounderco Wilson's advice is spot on in my books, right down to using cereal box paperboard as a homemade gasket in a pinch. I once had to do that and used gasket cement in that instance. It lasted for years without further issues. As I've mentioned to you before, gasket sealer is generally not needed between clean and undamaged water pump mating surfaces for the water pump -it's a relatively low pressure system. I don't recall seeing anywhere in actual Volvo service manuals or TSBs about using gasket sealer, leaving it up to the common sense and preferences of the installer.

Phil's also quite right in suggesting that water pump systems rarely fail without giving plenty of advance warning, often over a number of years, and the failure is usually weeping and slow coolant loss, not a sudden major leak or pump seizure. For any sudden failures it's typically the impeller detaching, which is more a function of design and build quality rather than installation and maintenance. I also agree it's a great opportunity to check pulley alignments and replace the rubber mounting bushings as needed.

The Volvo and Hepu pumps have weep holes in the casing, either above or below the water pump bearing, for inspection to give advance warning of bearing seal failure. I had one rather new replacement water pump in my B234F that had coolant in the weep hole that dealer service noted as imminent water pump failure on the invoice. The green coolant remained in sight for many more years without dripping or noticeable loss of coolant. I never did replace that water pump, it was fine, probably just a minor manufacturing issue that allowed a couple of drops a month to escape. (BTW to Phil, the 16-valve B234F uses the same water pump with no additional issues other than the larger valve cover is slighlty more prone to weeping oil at the front, getting oil onto the pump top seal if you continually neglect it).

Some posts here seem to be suggesting there is more than one rubber ring at the top under the head. It's a single rubber gasket, normally referred to as a mushroom shaped rubber gasket. The rubber gasket on the return heater coolant line at the back is generally referred to as a collar rubber gasket. It's almost never a source of leaks in my experience if adequately tightened at installation. Unfortunately, the clamping bolt at that rear connection is out of sight and easily ignored during removal and installation. Even after doing the job a number of times over the years, after 5 years of never doing it, I still often try to pull the water pump off before remembering that bolt.


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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now