My model 603 filter pump leaks at the top under cap

No. Its too cheap to buy a new one for that to be cost/hasstle effective.
new ones range from 20 - 50
Intex Krystal Clear Filter Pump Model 603 NEW Factory Sealed

Intex 1000 Gallon Filter Pump AC 110 to 120 Volt

Are you sure it is leaking from a spot "Originating" at the bottom? Many times this is what is seen, but the water is actually traveling down the side.

If at the bottom, you either have a cracked tank, or the drain cap is loose, missing the cap gasket or it is on "Cross Threaded"?

But... most likely from experience, it leaking at the valve clamp.

Have you tried running an extra duty extension cord to another plug, not in that circuit?? Your GFCI may be bad?? Pump drawing too many amps and the breaker not rated for those amps.. Bad pump??

I would try another plug first and work from there...

1. Unplug the washer.
2. Remove the 3 Torx head screws (located left, center, and right) from the front bottom kick panel of the washer.
3. The drain/filter/pump is right in front.
4. You can see a diagram of the pump at http://www.repairclinic.com/PartDetail/Drain-Pump/1200164.
5. First remove as much water from the washer as you can. Place a large towel under the pump - a lot of water will come out when you remove the filter cover cap.
6. Remove the drain filter cover cap by turning the filter cover cap counterclockwise.
7. Remove the filter and check the housing and pump impeller vanes for debris (see if you can move the pumps impeller by hand).
8. Clean the cover cap gasket and the gaskets mating surface.
9. Replace the filter and close the cover cap firmly.
10. Run a short wash cycle and check for any leaks at the filter cover cap. If the error comes back, you may need to replace your drain pump.
    
11. Replace the kick panel if none are found.

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

Top right corner: it means the bad right actuator could not pull down the lid seal on that side causing a leak. The actuators are sold in pair. They are not expensive. Replace both of them when you order them in. Need to inspect the rubber seal around the top lid since if it is distorted another 60 bucks to get a new lid for replacement also. The new lid comes with the york to engage with the actuators.

Look and listen for vacuum leak Free,Change air filter $15, change fuel filter$20, replace fuel pump$300.
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With motor running and your head under hood listen for hissing sound. Then start replaceing filters first air filter , then fuel filter. Check fuel pump by listening for humming noise at gas cap when you first move key in ignition to on (when the red lights go on). Have someone listen for you at the gas cap.(NO hum need pump)

Inspect the following: 1.(typical on these models) Possible cooling system caps leak allowing coolant to escape and air into the system. Replace if leaking (there are 2 caps- one cap on the top LH side of the engine and one on the radiator) 2. Radiator fan- This fan on the V-6s are hydraulic driven via powersteering pump, inspect for fluid leaks and proper fluid levels. (To test fan speed, unplug the switch located on the powersteering pump and rev motor to 2000 rpm fan should pick up speed)have it checked if problematic. 3. Replace the thermostat if this hasn't been done in the last 30,000miles, possible binding or stuck (located on the LH side of the engine, under the alternator and at the back end of the coolant feeder pipe). If these all check out fine, inspect or replace the water pump. To replace the pump it requires timing belt removal and or replacement. Hopefully this helps

If it is brand new and leaking, it sounds like your pool filter has a connection problem. Check your connections to make sure that they are tight and sound and that you do not have any hairline cracks.