by metalworker0 » Thu Jul 29, 2021 2:25 pm
You'll have to check properly with engine running where the leak is coming from .. and yes if there is a leak there is possibility that air is getting in .
I dont think you are going to be dropping the subframe .
i found this on this site about how to tell if air is getting into the system, its from the ford manual
A1: CHECK FOR AIR INGRESS INTO THE FUEL SYSTEM
CAUTION:
CAUTION:The generator must be protected from contamination. Failure to follow this instruction may cause premature failure of the generator
1
Protect the generator with lint-free material to prevent contamination (vehicles with 2.0 L diesel engine).
2
Using a suitable piece of clear plastic pipe, manufacture a pipe that may be installed between the fuel injection pump and the fuel filter return line.
3
Install the clear plastic pipe between the fuel injection pump and the fuel injection pump to fuel filter return line.
4
Start the engine, wait a few minutes and then visually observe the clear plastic pipe for signs of air ingress.
Are any signs of air present in the clear plastic pipe?
Yes
GO to A2. .
No
REMOVE the clear pipe and CONNECT the fuel return line to the fuel injection pump. For additional diagnostics for Fuel Charging and Controls REFER to Section [long list here]
A2: CHECK WHERE AIR IS ENTERING THE SYSTEM
1
Using suitable clean engine oil, apply the oil to each of the fuel supply and fuel return connections, unions and joints in turn and observe the clear pipe for visible signs of air after each oil application.
Did the amount air in the clear plastic pipe decrease when any of the connectors, unions or joints were oiled?
Yes
REPAIR the connector(s) or union(s) in question. Test the system for normal operation.
No
GO to A3. .
A3: CHECK THE FUEL FILTER HOUSING FOR SIGN OF AIR INGRESS
1
Ignition switch in position 0.
2
Disconnect the fuel injection pump return line from the fuel filter and the fuel filter to fuel tank return line.
3
Using a suitable connector, connect the fuel injection pump return line to the fuel filter to fuel tank return line.
4
Start the engine and observe the clear plastic pipe for visible signs of air.
Did the air decrease in the clear plastic pipe?
Yes
Air ingress is at the fuel filter or housing. REPAIR or INSTALL a new fuel filter or housing as necessary. Test the system for normal operation.
No
INSTALL a new fuel level sensor.