yo,
Time for baby powder; sprinkle it around suspect area(a) & start engine; hopefully the fan won't spread the fluid all over & you'll see the path in the gooey powder.
Or for a refundable deposit; rent a pressure tester at local parts store; test cap too w/adapter provided @ ~12psi
Pressure Test from 96 Bronco Workshop Manual; is 99.99998 = to your year; and btw, Upper Case is by Ford, not me;
WARNING: NEVER REMOVE THE RADIATOR CAP (8100) OR DEGAS BOTTLE CAP UNDER ANY CONDITIONS WHILE THE ENGINE (6007) IS OPERATING. FAILURE TO FOLLOW THESE INSTRUCTIONS COULD RESULT IN DAMAGE TO THE COOLING SYSTEM OR ENGINE OR PERSONAL INJURY. TO AVOID HAVING SCALDING HOT COOLANT OR STEAM BLOW OUT OF THE RADIATOR, USE EXTREME CARE WHEN REMOVING THE RADIATOR CAP OR DEGAS BOTTLE CAP FROM A HOT RADIATOR. WAIT UNTIL THE ENGINE HAS COOLED, THEN WRAP A THICK CLOTH AROUND THE RADIATOR CAP AND TURN IT SLOWLY TO THE FIRST STOP. STEP BACK WHILE THE PRESSURE IS RELEASED FROM THE COOLING SYSTEM. WHEN YOU ARE SURE ALL THE PRESSURE HAS BEEN RELEASED, PRESS DOWN ON THE RADIATOR CAP OR DEGAS BOTTLE CAP (STILL WITH A CLOTH), TURN AND REMOVE IT.
Shut the engine off.
Open hood and install protective fender covers.
When engine is cool, cautiously remove radiator cap or degas bottle cap.
Disconnect battery.
Adjust the radiator coolant level (fill or drain) to 25mm (one inch) below the filler neck opening before testing. Wipe clean, and then wet the rubber sealing surfaces in the cap and filler neck before installing the radiator cap tightly on the radiator.
Disconnect the electrical connector from the coolant temperature sending unit and remove the temperature sending unit from the engine.
With the radiator cap installed and the cooling system pressure relieved, only a small amount of coolant will be lost when the sending unit is removed.
Install the adapter fitting from Rotunda Radiator/Heater Core Pressure Tester 021-00013
or equivalent (male thread on one end, and a hose connector on the other end to accommodate the tester hose) tightly into the intake manifold (9424) or cylinder head in place of the sending unit.
1 8100 Radiator Cap
2 Filler Neck Seal
(Part of 107-01301)
3 Filler Neck Adapter
(Part of 107-01301)
4 Quick Disconnect Fittings
(Part of 107-01301)
5 Temperature Sender Pressure Hose Adapter
(Part of 107-01301)
6 Pressure Test Pump 021-00013 or Equivalent (Part of 107-01301)
7 Pressure Relief *****
(Part of 107-01301)
8 Radiator Cap Pressure Test Adapter (Part of 107-01301)
On Bronco, F-150, F-250, F-350 and F-Super Duty series vehicles, remove the radiator overflow hose from the overflow ******. Install a separate radiator overflow hose firmly on the overflow ******. Insert the free end of separate radiator overflow hose into container of water.
Attach the pressure pump and gauge to the adapter-fitting and pressurize the cooling system to 10 psi.
No bubbles should appear in the water container when the system is pressurized to the LOWER LIMIT (10 psi]). If the system is satisfactory at the lower limit, gradually increase the system pressure until a slight stream of bubbles appears in the water container. This is the release pressure of the pressure cap.
Replace any radiator cap or degas bottle cap that has a release pressure that is greater than the specified UPPER LIMIT pressure (13 psi]) without discharging bubbles.
If the radiator cap does not hold pressure, remove and wash the radiator cap or degas bottle cap in clean water to dislodge all foreign particles from the gaskets. Check the sealing surface in the radiator filler neck.
Inspect the cam lock flanges on both sides of the filler neck for maximum cap engagement.
Pressurize the cooling system as described in Step 6 (using a radiator cap and degas bottle cap that operate within the specified upper and lower pressure limits) and observe the gauge reading for approximately two minutes. Pressure should be held between 69 and 90 kPa (10 and 13 psi) and should not drop during this time.
If the pressure drops, check for leaks at the engine-to-heater core hoses, engine-to-radiator hoses, bypass hose, water valve hose (if applicable), thermostat housing gasket, radiator and heater core. Also refer to engine system checks if a leak cannot be located in the cooling system. Any leaks that are found must be corrected and the system checked again.
If the system holds pressure, proceed to next step.
Release the system pressure by loosening the radiator cap and removing the adapter. Install the water temperature indicator sender unit, check coolant level and replenish, if necessary, with the correct coolant solution.
NOTE: When the battery has been disconnected and reconnected, some abnormal drive symptoms may occur while the powertrain control module (PCM) relearns its adaptive strategy. The vehicle may need to be driven 10 miles or more to relearn the strategy.
Connect battery ground cable.
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Radiator Cap Pressure Test
Remove the radiator cap from the radiator filler neck.
Use water to clean the radiator cap in the area of the rubber seal and the vacuum relief valve as described in Radiator Cap in the Cleaning and Inspection portion of this section. Immerse the radiator cap in water to wet the seals and install on the shallow filler neck of Rotunda Radiator/Heater Core Pressure Tester Adapter 021-00013 or
equivalent. (The adapter is designed to accept both deep and shallow neck radiator caps.)
Before installing the radiator cap on the adapter, immerse the filler neck seal in water and install it in the filler neck adapter. If the adapter is made of plastic, check its sealing surfaces to be certain that they are free of rough spots and contain no parting lines or core marks.
The filler neck seal is reversible so that it may be used on either a deep or shallow radiator filler neck. It will also fit either end of the radiator cap pressure test adapter.
Install the filler neck adapter with filler neck seal on the deep filler neck end to the radiator cap pressure test adapter.
Connect the female quick disconnect fitting of the pressure test pump to the male quick disconnect fitting of the filler neck adapter.
SLOWLY depress the pump plunger of the pressure test pump until the pressure gauge reading stops increasing and note the highest pressure reading obtained. If the plunger of the pump is depressed too fast, an erroneous pressure reading will result.
Release the pressure by depressing the pressure relief valve stem. Then, tighten the pressure relief ***** and repeat Step 6 (at least twice) to make sure the pressure test reading is repeatable within the acceptable gauge reading limits of the radiator cap and is not erratic. Refer to Specifications at end of this section.
If the pressure test gauge readings are not within the acceptable gauge reading limits, replace the radiator cap, and perform the pressure test. If the pressure test gauge readings are within the acceptable gauge reading limits, perform the pressure test.
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for internal combustion leak; get block Checker such as NAPA's "block tester" ot;
http://www.blockchek.com/instructions.htm
