Well, do you have the Davco primary, or the proprietary Volvo one?
If you have the Davco, it's probably mounted on the right side of the vehicle, at the front of the engine compartment. Put a bucket underneath it to catch the fuel, and feel around the bottom and front.. there's a small plastic lever, in something of a reverse "L" shape... push down on it, and it'll drain the fuel. To get it out more smoothly, remove the breather cap.. you'll want to get a Davco wrench for this... you can buy them at any truck dealership or diesel shop... be careful, as there are three sizes of Davco wrenches... all the ones I've seen on trucks are the medium size.
If you have the other style, it'll be located on the left side of the vehicle, directly behind the suspended canister secondary fuel filter.. there's a knob on the bottom... rotate it counterclockwise, and it'll open up.
Located in front of the fuel filter you will find a yellow lever-like switch if you rotate the switch clockwise it will drain the fuel-water separator.
Little yellow lever (valve) on left side near bottom of fuel filter housing. Push lever and fuel will drain out of hose near bottom of truck.
under the truck on the inside of the driver side frame rail next to the transmission it looks like a little black thing the drain is in front of the circle
water separator removes water (liquid) but moisture separator removes water vapor
I am going to assume this is a diesel fuel water separator assembly. Install it in the fuel system as per the instructions contained in the package. Check and drain it on a regular basis. I drain mine every tank of fuel if I am unsure about the quality of fuel I am getting.
If you're talking about the one on the frame rail on the driver's side, there's a small black plastic lever which opened up the drain.
NO
Yellow lever attached to back of fuel filter in "V" of engine, the drain hose ends on front passenger side of block, under a heater hose, it drains about 6 to 8 ounce of fuel when drain is opened, and you want to catch the fuel in a clean jar to see if it has water. You may have to drain it a few times to get all the water out. Start engine between draining of separator, and make sure to close the drain valve after each draining. The water in fuel light should reset it's self.
Bad injector cups. Fairly common problem with Volvo engines.
you need a 15mm alan wrenchnand theres a plug on the side of the seperator under the drivers seat
circuit of bilge oil water separator
if it is a diesel it is built in to the fuel filter that is on top of the engine. on the 7.3l there is a yellow lever on the back of the housing that you can drain the water/fuel from it