tow FORD MUSTANG 2003 Owner's Manual

1. If compression improves considerably, piston rings are faulty.
2. If compression does not improve, valves are sticking or seating incorrectly.
3. If two adjacent cylinders indicate low compression pressures and squirting oil on each piston
does not increase compression, the head gasket may be leaking between cylinders. Engine oil
or coolant in cylinders could result from this condition.
Use the Compression Pressure Limit Chart when checking cylinder compression so that the
lowest reading is within 75 percent of the highest reading.
Cylinder Leakage Detection
When a cylinder produces a low reading, use of the Engine Cylinder Leak Detection/Air Pressurization
Kit will be helpful in pinpointing the exact cause.
The leakage detector is inserted in the spark plug hole, the piston is brought up to dead center on the
compression stroke, and compressed air is admitted.
Once the combustion chamber is pressurized, a special gauge included in the kit will read the
percentage of leakage. Leakage exceeding 20 percent is excessive.
While the air pressure is retained in the cylinder, listen for the hiss of escaping air. A leak at the intake
valve (6507) will be heard in the throttle body (9E926). A leak at the exhaust valve (6505) can be
heard at the tail pipe. Leakage past the piston rings will be audible at the positive crankcase ventilation
(PCV) connection. If air is passing through a blown head gasket to an adjacent cylinder, the noise will
be evident at the spark plug hole of the cylinder into which the air is leaking. Cracks in the cylinder
block or gasket leakage into the cooling system may be detected by a stream of bubbles in the radiator
(8005).
Oil Consumption Test
The following diagnostic procedure is used to determine the source of excessive internal oil
consumption. 1. NOTE: Oil use is normally greater during the first 16,100 km (10,000 miles) of service. As
mileage increases, oil use generally decreases. Vehicles in normal service should get at least
1,450 km per liter (900 miles per quart) after 16,000 km (10,000 miles) of service. High speed
driving, towing, high ambient temperature and other factors may result in greater oil use.
Define excessive oil consumption, such as the number of miles driven per liter (quart) of oil
used. Also determine customer's driving habits, such as sustained high speed operation,
towing, extended idle and other considerations.
2. Verify that the engine has no external oil leak as described under Engine Oil Leaks in the Diagnosis and Testing portion of this section.
3. Verify that the engine has the correct oil level dipstick (6750).
4. Verify that the engine is not being run in an overfilled condition. Check the oil level at least five minutes after a hot shutdown with the vehicle parked on a level surface. In no case should the
level be above MAX or the letter F in FULL. If significantly overfilled, carry out Steps 6a through
6d.
5. Verify the spark plugs are not oil saturated. If the spark plugs are oil saturated and compression is good it can be assumed the valve seals or valve guides are at fault. Klj . 9 ba
172003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

4. WORN RINGS OR DILUTED OIL: When the engine is accelerated (dotted needle), the needle
drops to 0 kPa (0 in- Hg). Upon deceleration, the needle runs slightly above 74 kPa (22 in- Hg).
5. STICKING VALVES: When the needle (dotted) remains steady at a normal vacuum but occasionally flicks (sharp, fast movement) down and back about 13 kPa (4 in- Hg), one or more
valves may be sticking.
6. BURNED OR WARPED VALVES: A regular, evenly- spaced, downscale flicking of the needle
indicates one or more burned or warped valves. Insufficient hydraulic lash adjuster or hydraulic
lash adjuster (HLA) clearance will also cause this reaction.
7. POOR VALVE SEATING: A small but regular downscale flicking can mean one or more valves are not seating.
8. WORN VALVE GUIDES: When the needle oscillates over about a 13 kPa (4 in- Hg) range at idle
speed, the valve guides could be worn. As engine speed increases, the needle will become
steady if guides are responsible.
9. WEAK VALVE SPRINGS: When the needle oscillation becomes more violent as engine rpm is increased, weak valve springs are indicated. The reading at idle could be relatively steady.
10. LATE VALVE TIMING: A steady but low reading could be caused by late valve timing.
11. IGNITION TIMING RETARDING: Retarded ignition timing will produce a steady but somewhat low reading.
12. INSUFFICIENT SPARK PLUG GAP: When spark plugs are gapped too close, a regular, small pulsation of the needle can occur.
13. INTAKE LEAK: A low, steady reading can be caused by an intake manifold or throttle body gasket leak.
14. BLOWN HEAD GASKET: A regular drop of fair magnitude can be caused by a blown head gasket or warped cylinder head- to-cylinder block surface.
15. RESTRICTED EXHAUST SYSTEM: When the engine is first started and is idled, the reading may be normal, but as the engine rpm is increased, the back pressure caused by a clogged
muffler (5230), kinked tail pipe or other concerns will cause the needle to slowly drop to 0 kPa
(0 in-Hg). The needle then may slowly rise. Excessive exhaust clogging will cause the needle to
drop to a low point even if the engine is only idling.
16. When vacuum leaks are indicated, search out and correct the cause. Excess air leaking into the system will upset the fuel mixture and cause concerns such as rough idle, missing on
acceleration or burned valves. If the leak exists in an accessory unit such as the power brake
booster (2005), the unit will not function correctly. Always fix vacuum leaks.
Excessive Engine Oil Consumption
The amount of oil an engine uses will vary with the way the vehicle is driven in addition to normal
engine- to-engine variation. This is especially true during the first 16,100 km (10,000 miles) when a new
engine is being broken in or until certain internal engine components become conditioned. Vehicles
used in heavy- duty operation may use more oil. The following are examples of heavy- duty operation:
z trailer towing applications
z severe loading applications
z sustained high speed operation Klj . 12 ba
172003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

GENERAL PROCEDURES
Valve Stem to Valve Guide Clearance
NOTE:
Valve stem diameter must be within specifications before checking valve stem to valve guide
clearance.
1. NOTE: If necessary, use a magnetic base.
Install a Valve Guide Clearance Gauge on the valve stem and install a Dial Indicator Gauge with
Holding Fixture. Lower the valve until the Valve Guide Clearance Gauge contacts the upper
surface of the valve guide.
2. Move the Valve Guide Clearance Gauge toward the indicator and zero the indicator. Move the Valve Guide Clearance Gauge away from the indicator and note the reading. The reading will
be DOUBLE the valve stem- to-valve guide clearance. Valves with oversize stems will need to
be installed if out of specification.
SECTION 303-
00: Engine System — General Information 2003 Mustang Workshop Manual Special Tool(s)
Dial Indicator Gauge with
Holding Fixture
100-
002 (TOOL- 4201-C) or
equivalent Clearance Gauge, Valve Guide
303-
004 (TOOL- 6505-E) or
equivalent Klj . 1 ba
22003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

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
62003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

16.
CAUTION: The cap screw is hidden; make sure to remove it or the engine front
cover will be damaged.
NOTE: Record the location, type and size of the fasteners.
Remove the engine front cover. zSlide the engine front cover off the two dowels.
z Remove and discard the engine front cover gasket.
Installation 1. CAUTION: In order to prevent foreign material from contaminating the engine block
or the engine front cover it is necessary to seal the coolant and oil passages of both
components. Failure to follow these directions will result in engine damage.
CAUTION: Do not use a surface conditioning pad or any other type of fibrous
abrasive disc to clean the gasket surfaces. Failure to follow these directions will result in
engine damage.
Clean and inspect the engine block and front cover as follows:
zPack the exposed portion of the oil pan with clean shop towels.
z Plug the oil and coolant passages.
z Clean the gasket surfaces.
z Clean all surfaces requiring gasket sealant with metal surface cleaner.
z Using compressed air, remove any remaining foreign material from the engine block and
engine front cover.
z Remove the shop towels from the oil pan.
z Remove the plugs or seals from the engine block and engine front cover. Klj . 4 ba
92003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

CAUTION: Do not damage the cylinder wall with the sharp edges of the connecting
rod.
Install the piston with the arrow on the piston face pointing toward the front of the engine.
16. CAUTION: Inspect the connecting rod bearing clearance. For additional information,
refer to Section 303 - 00 .
CAUTION: The connecting rod cap will fit only one way.
Position the connecting lower rod bearing and the connecting rod cap on the connecting rod
and the crankshaft journal.
17. Install the rod caps. Tighten the bolts in three stages: zStage 1: Tighten to 25 Nm (18 lb- ft).
z Stage 2: Tighten to 45 Nm (33 lb- ft).
z Stage 3: Tighten an additional 105 degrees. 18. Install the remaining pistons and the connecting rods. Klj . 7 ba
282003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

55.
NOTE: The hydraulic lash adjusters must be reinstalled in their original locations. Record the
hydraulic lash adjuster locations.
Remove the hydraulic lash adjusters.
RH cylinder head 56. CAUTION: The cylinder head must be cool before removing it from the engine.
Cylinder head warpage can result if a warm or hot cylinder head is removed.
CAUTION: Place clean shop towels over exposed engine cavities. Carefully remove
the towels so foreign material is not dropped into the engine.
CAUTION: The cylinder head bolts must be discarded and new bolts installed. They
are tighten- to-yield designed and cannot be reused.
CAUTION: Do not use metal scrapers, wire brushes, power abrasive discs or other
abrasive means to clean the sealing surfaces. These tools cause scratches and gouges
that make leak paths. Use a plastic scraping tool to remove all traces of the head gasket.
CAUTION: Aluminum surfaces are soft and can be scratched easily. Never place the
cylinder head gasket surface, unprotected, on a bench surface.
Remove the bolts and the RH cylinder head.
zDiscard the cylinder head gasket.
z Discard the cylinder head bolts. Klj . 18 ba
212003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

LH cylinder head
57. CAUTION: The cylinder head must be cool before removing it from the engine.
Cylinder head warpage can result if a warm or hot cylinder head is removed.
CAUTION: Place clean shop towels over exposed engine cavities. Carefully remove
the towels so foreign material is not dropped into the engine.
CAUTION: The cylinder head bolts must be discarded and new bolts installed. They
are tighten- to-yield designed and cannot be reused.
CAUTION: Do not use metal scrapers, wire brushes, power abrasive discs or other
abrasive means to clean the sealing surfaces. These tools cause scratches and gouges
that make leak paths. Use a plastic scraping tool to remove all traces of the head gasket.
CAUTION: Aluminum surfaces are soft and can be scratched easily. Never place the
cylinder head gasket surface, unprotected, on a bench surface.
Remove the bolts and the LH cylinder head.
zDiscard the cylinder head gasket.
z Discard the cylinder head bolts. Klj . 19 ba
212003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

DISASSEMBLY AND ASSEMBLY OF SUBASSEMBLIES
Piston
Disassembly
1. Press the piston pin out of the connecting rod and piston assembly.
2. Remove the connecting rod from the piston.
3. Clean and inspect the piston and connecting rod. For additional information, refer to Section 303 - 00 .
Assembly 1. NOTE: Connecting rod must be installed into piston with identification markings toward front.
Position the connecting rod in the piston.
SECTION 303-
01B: Engine — 4.6L (2V) 2003 Mustang Workshop Manual Material
Item Specification
Super Premium SAE 5W-20
Motor Oil
XO- 5W20- QSP or equivalent WSS-
M2C153-
H Klj . 1 ba
32003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

2. Press the piston into the piston and connecting rod assembly.
3. Install the piston rings.
1. Using a suitable ring expander tool install the upper compression ring with the top side identification mark towards the dome.
2. Using a suitable ring expander tool install the lower compression ring with the top side
identification mark towards the dome.
3. NOTE: Assemble with end gaps up.
Using a suitable tool install the piston oil control segment ring spacer.
4. NOTE: Install one segment ring above and one segment ring below the spacer.
Using a suitable tool install the piston oil control segment rings.
5. Orient the upper compression ring gap to the center line at the rear of the piston, parallel to the wrist pin bore.
6. Orient the oil control ring gaps as shown.
7. Orient the expander ring gap and lower compression ring gap as shown. Klj . 2 ba
32003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...