I've just removed the water pump from my '98 V90. After removal of the top shroud and close inspection, I became suspicious that the slow leak this car has had is very possibly due to a gasket failure, and not the pump itself. Upon removal of the pump, I believe I have confirmed this. It appears to me that coolant was leaking past the bottom dowel pin. There's quite a bit of discoloration in this area, and the rest of the gasket is its normal green color. The water pump itself is in excellent shape, but since I've already bought a replacement, I'll go ahead and install it. Keep the old one for an emergency spare or something.

The old gasket, which is green and the clay/paper type, was mounted dry. The new gasket is rather thin fiber. I plan to mount it dry as well, but I'm wondering if it might not be a good idea to use a bit of sealer around the two dowels.

Any thoughts on this? If you would use sealer, what sort would you go with?

In theory you should not need a sealer but it never hurts. I have used silicone sealers made for the purpose. Any gasket sealer such a permatex will work well though. If there is any sign of corrosion or damage on the mating surfaces use the sealer for sure.

Changing the timing belt while in there?
--
David Hunter

Hey David,

Thanks for the response. Yeah, I went to the parts store and picked up a small tube of Versachem Mega Gray, which mentioned on the packaging that it was specifically meant for water pumps and thermostat housings.

There was no evidence of corrosion, but since I wanted to be sure that this same leak never appears again, I went ahead and gave it a thin coating of the sealer on both sides of the gasket. The old gasket came away from the block surface almost intact. A couple small pieces remained, and I used a small artist's pallet knife to remove them. I then used some 0000 steel wool to buff away all remaining traces of the old gasket. After the repairs were complete, I ran the engine for about a half hour and there were no signs of leaks.

Actually, no, I didn't replace the timing belt. The timing belt was replaced less than 10,000 miles ago, and when we had the belt replaced, we also had the pulley(s) replaced as well. So, I just didn't see much point to replacing it again. I would not recommend replacing the water pump only, however, unless the belt and its pulleys had a low mileage count on them. We probably should have had the water pump replaced when we had the belt done, and this additional repair would not have been necessary. But I suppose things worked out okay in the end. We have a spare water pump now that is in excellent condition, plus I have gained the experience to see what is involved in a timing belt replacement, and I would now have to agree with the others that this is an easier task than replacing the belt on a B21/23/230 engine. So when it's due for replacement in another 60k miles or so, I'll do it myself, and save hundreds of dollars.

BTW, I followed the instructions in the FAQ for this repair, but modified things since I wasn't going to replace the belt. It is actually a fairly simple job if one is replacing the water pump only. I did not have to remove the timing belt from the cam pulleys or the crank sprocket. I didn't need to take the rest of the top shroud loose either. All I had to do was remove the shroud's front cover, remove the belt tensioner, tuck the belt out of the way, and then I was able to remove the water pump. Just to be sure, however, I marked the position of the cam wheels and belt in relation to the shroud using white out, and was careful not to disturb the belt's position on the crank sprocket.

I used a 5/64" drill bit to hold the tensioner's piston in place after compressing it in a vise. The tip about letting the tensioner rest momentarily between compressions was very helpful.

Upon reassembly, I double and triple and even quadruple checked that the belt was tensioned properly between the tensioner pulley and the crank after the tensioner was installed and before I removed the drill bit. I also made sure the alignment marks I had made were still, um, aligned. Everything was good, and after pulling the drill bit, everything tightened up perfectly. It was most reassuring :)

Best,
Michael