gas mileage FORD MUSTANG 2003 Workshop Manual

DESCRIPTION AND OPERATION
Maintenance Schedule —
Vehicles with Gasoline Engines
The maintenance schedule is designed to protect against major repairs resulting from neglect or
inadequate maintenance and to prolong the life of the vehicle.
General Maintenance Information
NOTE: This is a generic maintenance schedule for all Ford, Lincoln and Mercury vehicles. There may
be items listed that do not apply to all vehicles.
The Normal Schedule applies to operation of the vehicle under typical, everyday driving conditions.
The maintenance frequency in this schedule typifies what the vast majority of vehicles will require. The
listed services should be carried out at specified mileage intervals. There are, however, additional
services required that only the noted vehicles require.
If the vehicle is operated in one or more of the following special operating conditions, those additional
services will be required. The special operating conditions are:
ztowing or carrying heavy loads.
z extensive idling and/or driving at low speeds for long distances.
z driving in dusty conditions.
z off- road operation.
There are also exceptions to the Normal Operating Schedule which will require more frequent
maintenance for some components. Those exceptions are:
znatural gas and propane vehicles — fuel tank intervals.
z normal vehicle axle — maintenance and lubrication.
z police and taxi vehicles — maintenance and lubrication.
z engine oil and yellow coolant — time and mileage-based interval.
Special Operating Condition Requirements
When towing a trailer or using a camper or car- top carrier:
z Change engine oil and install a new oil filter every 4,800 km (3,000 miles) or 3 months.
z Change transfer case fluid every 96,000 km (60,000 miles).
z Change manual transmission fluid as required.
z Inspect and lubricate U- joints as required.
During extensive idling and/or low speed driving for long distances, as in heavy commercial use such
as delivery, taxi, patrol car or livery: SECTION 100-
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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
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