I have replaced the entire front suspension on my 1992 Subaru Legacy Wagon, but I am still hearing noise coming from that area. The front struts are 1.5 years old.

SOURCE: Subaru Outback - '03 boxer 2.5L engine sounds like a diesel

heavier oil if you are not in a cold climate. but before you do that have the oil pressure checked. We used to use a can of STP every once in a while on a motor in a dodge we had... nothing wrong with it... was just noisy.

Robert

SOURCE: How do you replace the fuel pump in 1992 2wd Subaru Legacy Wagon

1. Relieve the fuel system pressure.
2. Disconnect the negative battery cable.
3. Remove the rear exhaust pipe and muffler assembly.
4. On All Wheel Drive (AWD) vehicles, remove the rear differential assembly and the rear crossmember. You do not have AWD so this step is not for you
   
5. Remove the fuel filler cap and drain the fuel into a suitable container.
6. Remove the fuel filler pipe protector.
7. Raise and support the vehicle safely on jackstands.
8. Remove the fuel filler, air vent and delivery hoses.
9. On AWD vehicles, disconnect the air breather hoses and evaporation hose from the pipes.
10. Support the fuel tank with a floor jack or equivalent lifting device.
11. Loosen the attaching bolts and lower the fuel tank slightly.
12. Disconnect the fuel pump harness
    

SOURCE: Info on replacing water pump on Subaru Legacy

The water pump is run by the timing belt.Involves the draining the antifreeze,removing the radiator/condensor fan motors,harmonic balancer,alt./ac./p.s. belts, timing covers and timing belt.Along with a new pump,a new timing belt should installed.Timing marks are critical and it should be repairer by a garage.Should take about 1 to 2 hours or so to do if everything comes apart easy.Also there is no cap or rotor,only a coil pak.Hope this gives you a better idea.

SOURCE: 1992 Subaru legacy ls wagon w/air suspension. Air

your shocks are leaking or a leak in the lines or pump it has a rolling diaphram when you hit a speed they lower and raise on speed

if you cant find the leak you can pump the strut with a compressor if it has a leak replace it if they are expensive and you wish a cheeper fix you can cap off the front lines or rear or replace all of them with regular coils and struts if off a used car the struts may be bad the spring is heavy and the strut needs to be removed and checked if its bad get new ones they are not cheep but the air ride struts new are a grand or better well they use to be a used one was a few hundred i replaced them with springs on a gl-10 years ago and the light may blink remove the bulb or a wire under the drivers side seat not sure on that year