Service Procedure - Diagnosis

1. Perform Steps 1 and 2 of the block diagram shown in Figure 1. Perform a visual inspection to determine the general area of the oil leak.

2. After determining the "Findings" of Step 2, perform Step 3 by following Procedures A, B, C or D, whichever is appropriate, up to, but not including the air pressure test.

NOTE:
WHEN THE FINDINGS RESULT IN FOLLOWING PROCEDURE "A" FOR "LEAKS OIL AT REAR END", IT IS VERY IMPORTANT TO FOLLOW THE BLOCK DIAGRAM INSTRUCTIONS TO REMOVE THE TRANSMISSION, IF AN AEROSTAR, AND TO REMOVE THE ENGINE, IF AN EXPLORER/RANGER. THE PRACTICE OF REMOVING EXPLORER/RANGER OIL PANS WITH ENGINE IN VEHICLE CAN RESULT IN FAULTY DIAGNOSIS AND/OR REPAIR FOR THE PURPOSES OF THIS TSB.

If the leak has not been located and corrected at this point, then fabricate a device that is capable of applying a constant 1 to 3 psi of air pressure to the engine crankcase. The Rotunda Leak Tester 134-00003, or equivalent, which contains a pressure regulator and gauge capable of a 1 to 3 psi range, may be used.

3. Verify the location of the oil leak by pressurizing the engine crankcase with a constant supply of 3 psi of air pressure and the use of leak detection solution (liquid detergent and water). This process will verify the exact location of the leak. Dye and black light will verify a leak is present, but may not verify the exact location of the leak.

a. Assemble the necessary hose and fittings to connect an air pressure regulator and air pressure gauge to the shop air supply and to the engine crankcase through the dipstick tube.

b. Test the device to make sure 1-3 psi of air pressure can be maintained. Bursts of pressure over 3 psi can damage engine seals.

c. Before starting the test, make sure the regulator valve is completely closed so as not to accidentally apply a big burst of air to the engine when starting the test.

d. Attach the outlet (regulated) hose from the regulator/gauge device to the dipstick.

e. To trap air in the engine, plug any ports and passages (PCV valve, air inlet connection) that will allow air to escape.

f. Slowly open the regulator valve until 1-3 psi of air pressure registers on the gauge.

g. Keeping air pressure applied, brush or squirt a solution of liquid detergent and water or commercially available liquid leak detector (Snoop, Bubbles) to the primary area identified in Step 2 of the block diagram.

^ If the primary area is in the rear seal area, apply the solution to the rear seal, rear cap, rear cap to cylinder block and oil pan gasket areas.








^ If bubbles are detected only at the oil pan gasket, between the oil pan and the cylinder block, or between the oil pan and the rear main cap, only the oil pan gasket needs replacing. Note Procedure A, Figure 2, Step A3/F1, and pictorial, Figure 5. Proceed to SERVICE PROCEDURE - REPAIR REAR END OIL LEAK, Procedure A1.

^ If bubbles are detected between the rear main cap and the cylinder block, the rear cap must be removed and resealed. Note Procedure A, Figure 2, Step A3/F2, and pictorial, Figure 5. Proceed to SERVICE PROCEDURE - REPAIR REAR END OIL LEAK, Procedure A2.

^ If bubbles are detected between the rear seal lip and crank hub, a new rear oil seal will be required. Under certain circumstances, as outlined in the block diagram, it will be necessary to call the 4.OL Hotline. Note Procedure A, Figure 2, Step A3/F3, and pictorial, Figure 5. Proceed to SERVICE PROCEDURE - REPAIR REAR END OIL LEAK, Procedure A3.

^ If no bubbles are detected, but oil is present in the area between the crank hub and the lip of the rear seal, carefully remove the seal and inspect the crankshaft rear seal journal. (A leak may occur at the rear seal only when the engine is running.) Note Procedure A, Figure 2, Step A3/F3, and pictorial, Figure 5. Follow repair procedures outlined on the block diagram.

NOTE:
ANY APPEARANCE OF RUST, PITTING, POROSITY, OR NICKS ON THE REAR SEAL JOURNAL WILL CAUSE A LEAK.

^ If bubbles are detected at the front or rear of the intake manifold gasket, a new intake manifold gasket (FOTZ-9439-A) will have to be installed. Proceed to SERVICE PROCEDURE - REPAIR FOR OIL LEAKS AT INTAKE MANIFOLD, PROCEDURE B.

^ If bubbles are detected at the rocker cover rails, new rocker cover gaskets (F3TZ-6584-A) will have to be installed. Proceed to SERVICE PROCEDURE - REPAIR FOR OIL LEAKS AT ROCKER COVER RAILS, PROCEDURE C.

^ If bubbles are detected at the front end of the engine, a new front seal (E6TZ-6700-A) or oil pan gasket (FOTZ-6710-C) will be required. Proceed to SERVICE PROCEDURE - REPAIR FOR OIL LEAKS AT THE FRONT END, PROCEDURE D.