2003 FORD MUSTANG oil pressure

z
incorrectly functioning valve tappet
z air in lubrication system
z excessive valve guide wear
z low oil pressure
Excessive collapsed valve tappet gap can be caused by loose rocker arm seat bolts/nuts, incorrect
initial adjustment or wear of valve tappet face, or worn roller valve tappets, push rod (6565), rocker
arm (6564), rocker arm seat or valve tip. With valve tappet collapsed, check gap between the valve tip
and the rocker arm to determine if any other valve train parts are damaged, worn or out of adjustment.
An incorrectly functioning valve tappet can be sticking, caused by contaminants or varnish inside the
tappet. The tappet can have a check valve that is not functioning correctly, which can be caused by an
obstruction, such as dirt or chips that prevent the check valve from closing, or a broken check valve
spring. A tappet with a leakdown time out of specification can cause tappet noise. If no other cause for
noisy valve tappets can be found, the leakdown rate should be checked and new valve tappets
installed if found to be out of specification.
Assembled valve tappets can be tested with Hydraulic Tappet Leakdown Tester to check the leakdown
rate. The leakdown rate specification is the time in seconds for the plunger to move a specified
distance while under a 22.7 kg (50 lb) load.
Air bubbles in the lubrication system will prevent the valve tappet from supporting the valve spring
load. This can be caused by too high or too low an oil level in the oil pan or by air being drawn into the
system through a hole, crack or leaking gasket on the oil pump screen cover and tube. Klj . 17 ba
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4. Inspect for normal burning.
zCheck for light tan or gray deposits on the firing tip.
5. Inspect for pre- ignition, identified by melted electrodes and a possibly damaged insulator.
Metallic deposits on the insulator indicate engine damage. This may be caused by incorrect
ignition timing, wrong type of fuel or the unauthorized installation of a heli- coil insert in place of
the spark plug threads.
zInstall a new spark plug.
6. Inspect for overheating, identified by a white or light gray spots and with bluish- burnt
appearance of electrodes. This is caused by engine overheating, wrong type of fuel, loose spark
plugs, spark plugs with an incorrect heat range, low fuel pump pressure or incorrect ignition
timing.
zInstall a new spark plug. Klj . 2 ba
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SPECIFICATIONS
SECTION 303-
01A: Engine — 3.8L 2003 Mustang Workshop Manual General Specifications
Item Specification
Lubricants and Sealants
SAE 5W-
20 Premium Synthetic Blend Motor Oil
XO- 5W20- QSP WSS-
M2C153- H Gasket and Trim Adhesive F3AZ-19B508-
AA ESE-
M2G52- A Pipe Sealant with Teflon® D8AZ-19554-
A WSK-
M2G350- A2 Silicone Gasket and Sealant F7AZ-19554-
EA WSE-
M4G323- A4 Metal Surface Cleaner F4AZ-19A536-
RA WSE-
M5B392- A Engine
Displacement 3.8L
Number of cylinders 6
Bore 96.8325 mm (3.81 in)
Stroke 86.0 mm (3.39 in)
Firing order 1-4-2-5-3-
6 Oil pressure (hot 2,500 rpm) 40-
125 psi Oil capacity 5 quarts w/filter change
Compression ratio —
Cylinder Head and Valve Train
Cylinder head gasket surface flatness 0.18 mm (0.007 in)
Combustion chamber volume 61.5-
64.5 cc Valve arrangement (front to rear) —
Valve guide bore diameter 7.015-
7.044 mm (0.276- 0.277 in) Valve stem diameter —
intake 6.955-
6.988 mm (0.2738- 0.2751 in) Valve stem diameter —
exhaust 6.929-
6.962 mm (0.2728- 0.2741 in) Valve stem diameter —
oversize (intake) 9.075-
9.055 mm (0.3573- 0.3565 in) Valve stem diameter —
oversize (exhaust) 9.063-
9.043 mm (0.3568- 0.3560 in) Valve stem diameter —
oversize (intake) 9.456-
9.436 mm (0.3723- 0.3715 in) Valve stem diameter —
oversize (exhaust) 9.444-
9.424 mm (0.3718- 0.3710 in) Valve stem-
to-guide clearance — intake 0.020-
0.069 mm (0.045- 0.090 in) Valve stem-
to-guide clearance — exhaust 0.038-
0.083 mm (0.0015- 0.0033 in) Valve head diameter —
intake 47.27 mm (1.86 in)
Valve head diameter —
exhaust 37.1 mm (1.46 in)
Valve face runout 0.05 mm (0.002 in)
Valve face angle 45.675 degrees
Valve seat width 1.5-
2.0 mm (0.06- 0.08 in) Valve seat runout (T.I.R.) 0.076 mm (0.003 in) Klj . 1 ba
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A/C compressor bracket-
to-cylinder head stud bolt 25 18 —
Oil level indicator tube-
to-cylinder head bolt 10 — 89
Coolant recovery reservoir bracket-to-
GOP bolts 9 — 80
Motor mount-
to-subframe nuts 115 85 —
Oil pan drain plug 26 19 —
Wire harness bracket to motor mount nut 27 20 —
Steering column pinch bolt 47 35 —
Front subframe-
to-body bolts 90 66 —
Front subframe-
to-shock tower bolts 115 85 —
Oil pan-to-
cylinder block bolts a — — —
Oil pan-to-
transmission bell housing 45 33 —
Main bearing bridge nuts 32 24
Oil pump cover-
to-engine front cover bolts 25 18 —
Oil pump cover-
to-engine front cover bolt 10 89 —
Oil pickup tube-
to-cylinder block bolts 25 18 —
Oil pickup tube-
to-oil pan baffle nut 48 35 —
Flywheel-
to-crankshaft bolts 80 59 —
Wire harness bracket-
to-motor mount stud- nut 27 20 —
Engine ground strap-
to-motor mount nut 27 20 —
Motor mount-
to-motor mount bracket bolts 70 52 —
RH motor mount-
to-motor mount bracket nut 70 52 —
Hood ground strap-
to-hood hinge bolt 12 9 —
Hood hinge nuts 12 9 —
Generator mounting bracket 25 18 —
Power steering pump bracket nuts 8 — 71
Power steering pump bolts 25 18 —
Valve tappet guide plate bolts 12 9 —
Generator positive cable nut 10 — 89
Power steering pressure tube to pump nut 40 30 —
Accelerator cable bracket-
to-intake manifold bolts 10 — 89
42-
pin connector bolt 10 — 89
Transmission oil cooler tube bracket-
to-motor mount bracket nut 27 20
Torque converter-
to-flywheel nuts 36 27 —
Engine-
to-transmission bolts 40 30 —
Engine mount bracket-
to-engine bolts 70 52 —
Engine mount bracket-
to-engine nuts 70 52 —
Water pump pulley bolts 25 18 —
Oil filter
b — — —
Upper intake manifold-
to-lower intake manifold bolts a — — —
Lower intake manifold-
to-cylinder head bolts a — — —
Rocker arm pivot-
to-cylinder head bolts a — — — Klj . 5 ba
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Cylinder Block and Lower End Components 9 18801 Radio ignition interference capacitor
10 12281 Ignition wire set —
LH 11 18696 Tube assembly
12 9424 Intake manifold (lower)
13 9439 Intake manifold gasket —
RH 14 9439 Intake manifold gasket —
LH 15 9A424 Intake manifold seal (rear)
16 6A008 Cylinder head-
to-block dowel 17 6010 Cylinder block
18 6A373 Engine rear plate (automatic transmission)
19 6375 Flywheel (automatic transmission)
20 6375 Flywheel (manual transmission)
21 6A372 Engine rear plate (manual transmission)
22 6723 Oil pan rear seal
23 6675 Oil pan
24 7120 Pilot bushing
25 9278 Oil pressure sensor
26 9B339 Oil pressure sensor fitting
27 9A424 Intake manifold seal (front)
28 18663 Heater water outlet tube
29 8255 Thermostat housing-
to-intake manifold gasket 30 8592 Water outlet connection
31 9875 Water thermostat
32 9D475 EGR valve
33 9H465 Vacuum control solenoid
34 9723 Accelerator cable bracket
35 9E936 Throttle body gasket
36 9J433 EGR transducer
37 9E498 Vacuum hose
38 12280 Ignition wire set —
RH Klj . 5 ba
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22. Disconnect the engine oil pressure sender electrical connector.
23. Remove the pin-
type retainer.
24. Disconnect the crankshaft position (CKP) sensor electrical connector.
25. Remove the engine wiring harness.
26. Remove the stud bolt. Klj . 7 ba
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63. Connect the engine oil pressure sender electrical connector.
64. Connect the camshaft position (CMP) sensor electrical connector.
65. Connect the cylinder head temperature (CHT) sensor.
66. Install the fuel injectors and the fuel injection supply manifold as an assembly. For additional
information, refer to Section 303 - 04A .
67. Install a new upper intake manifold gasket. Klj . 21 ba
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70. Connect the differential pressure feedback EGR system electrical and vacuum connections.
71. Connect the vacuum hoses.
72. Install the positive crankcase ventilation (PCV) tube.
73. Connect the ignition coil and the radio interference capacitor electrical connectors.
74. Position and connect the LH spark plug wires. Klj . 23 ba
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