2003 FORD MUSTANG spark plugs

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~ ...

Valve Train Analysis—
Engine Running
z Start the engine and, while idling, check for correct operation of all parts. Check the following:
Valve Train Analysis— Engine Running, Valves and Cylinder Head
z Check for plugged oil drain back holes.
z Check for missing or damaged valve stem seals or guide mounted valve stem seals.
z Check for a plugged oil metering orifice in the cylinder head oil reservoir (4.6L engine only).
If insufficient oiling is suspected, check oil passages for blockage, then accelerate the engine to 1,200
rpm with the transmission in NEUTRAL and the engine at normal operating temperature. Oil should
spurt from the rocker arm oil holes such that valve tips and camshaft roller followers are well oiled.
With the valve covers (6582) off, some oil splash may overshoot camshaft roller followers.
Valve Train Analysis— Engine Running, Camshaft Lobe Lift— OHC Engines
Check the lift of each camshaft lobe in consecutive order and make a note of the readings. 1. Remove the valve covers.
2. Remove the spark plugs.
3. Install the Dial Indicator Gauge with Holding Fixture so the rounded tip of indicator is on top of the camshaft lobe and on the same plane as the valve tappet.
4. Rotate the crankshaft using a breaker bar and socket attached to the crankshaft pulley retainer bolt. Rotate the crankshaft until the base circle of the camshaft lobe is reached.
5. Zero the dial indicator. Continue to rotate the crankshaft until the (1) high- lift point of the
camshaft lobe is in the fully- raised position (highest indicator reading).
6. To check the accuracy of the original indicator reading, continue to rotate crankshaft until the (2) base circle is reached. The indicator reading should be zero. If zero reading is not obtained,
repeat Steps 1 through 6.
7. NOTE: If the lift on any lobe is below specified service limits, install a new camshaft, and new
camshaft roller followers.
Remove the Dial Indicator Gauge with Holding Fixture.
8. Install the spark plugs. Klj . 15 ba
172003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

9. Install the valve covers.
Valve Train Analysis— Engine Running, Camshaft Lobe Lift— Push Rod Engine
Check the lift of each lobe in consecutive order and make a note of the readings. 1. Remove the valve covers.
2. Remove the rocker arm seat bolts, rocker arm seat (6A528) and rocker arms.
Typical Engine With Push Rods
3. Make sure the valve tappet is seated against camshaft (6250). Install (1) Dial Indicator Gauge with Holding Fixture so the ball socket adapter of the indicator is on top of the valve tappet or (2)
Dial Indicator Gauge Adapter is on top of push rod and in same plane as valve tappet push rod
movement.
4. Remove the spark plugs.
5. Connect an auxiliary starter switch in the starting circuit. Crank the engine with ignition switch in OFF position. Bump crankshaft over until valve tappet is on base circle of camshaft lobe. At this
point, valve tappet will be in its lowest position. If checking during engine assembly, turn
crankshaft using a socket or ratchet.
6. Zero the dial indicator. Continue to rotate crankshaft slowly until valve tappet is in fully- raised
position (highest indicator reading).
7. NOTE: If lift on any lobe is below specified service limits, install a new camshaft, and new valve
tappets.
Remove the Dial Indicator with Holding Fixture, Dial Indicator Gauge Adapter, and auxiliary
starter switch.
8. Install rocker arm seats, rocker arms and rocker arm seat bolts.
9. Install valve covers.
10. Install spark plugs.
Valve Train Analysis— Engine Running, Valve Tappet
Valve tappet noise can be caused by any of the following:
zexcessive valve tappet gap (collapsed) Klj . 16 ba
172003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

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
32003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

DISASSEMBLY AND ASSEMBLY OF SUBASSEMBLIES
Cylinder Head
Disassembly and Assembly
CAUTION: If the components are to be reinstalled, they must be installed in the same
position. Mark the components removed for location.
1. Remove the spark plugs (12405) if necessary.
2. Using the special tool, compress the valve springs (6513).
3. Remove the following: 1. The valve spring retainer key (6518).
2. The valve spring retainers (6514).
3. The valve springs (6513).
4. The valve stem seals and seats (6A517).
SECTION 303-
01A: Engine — 3.8L 2003 Mustang Workshop Manual Special Tool(s)
Compressor, Valve Spring
303-
163 (T81P-6513- A)
Material Item Specification
SAE 5W-
20 Premium Synthetic
Blend Motor Oil
XO- 5W20-QSP or equivalent WSS-
M2C153-
H Klj . 1 ba
22003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

a
Refer to the procedure in this section. Power steering reservoir bolts 10 — 89
Water outlet connector bolts 25 18 —
Camshaft cap cluster to cylinder head bolts 10 — 89
Torque converter nuts 25 18 —
Timing chain tensioner bolts 25 18 —
Transmission filler tube bolt 47 35 —
A/C compressor bolts 25 18 —
Ignition coil bolts 6 — 53
Generator brace bolts 10 — 89
Primary timing chain guide-
to-engine bolts 10 — 89
Accelerator cable bracket bolts 10 — 89
Rear seal retainer bolts 10 — 89
Pressure plate bolts 2 — 47
Spark plugs 18 13 —
Crankshaft timing bolt sensor assembly 10 — 89
Camshaft timing bolt sensor assembly 10 — 89
Fuel rail studs 10 — 89
Engine coolant sensor 15 11 —
Exhaust manifold—
stud to cylinder head 10-
13 7-10 —
Throttle body adaptor bolts
a — — —
Throttle body bolts 10 — 89
Idle air control valve 10 — 89
RFI capacitor nut 10 — 89
Generator bolts 25 18 —
Oil pan drain plug 14 10 —
Water bypass tube bracket bolt 25 18 —
Subframe bolts 115 85 —
Battery lead to generator 10 — 89
EGR vacuum regulator solenoid bracket 10 — 89
Pipe plug—
water drain 20 15 —
Screen and cover assembly to main bearing cap stud spacer 25 18 —
Wiring harness retainer nut 10 — 89
Oil pressure switch
a — — —
A/C muffler stud to cylinder head 10 — 89
EGR tube to exhaust manifold connector 50 37 — Klj . 5 ba
62003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

4. Remove the bolts and the eight ignition coils.
5.
NOTE: Use compressed air to remove any foreign material from the spark plug wells before
removing the spark plugs.
Remove the spark plugs.
6. NOTE: Rotate the camshaft to the base circle of the camshaft lobe before removing the
followers. Keep the roller followers in order when removing.
Using the special tool, remove the 16 roller followers.
zRotate the crankshaft and camshaft as necessary. Klj . 2 ba
132003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

16. Remove the paper clip from the RH and the LH timing chain tensioners.
17.
NOTE: Rotate the camshaft to the base circle of the camshaft lobe before installing the roller
followers.
NOTE: Keep all the roller followers in order when installing.
Using the special tool, install the 16 roller followers.
18. Install the eight spark plugs. Klj . 11 ba
132003 Mustang Workshop Manual
17. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...