1991 1999 ford explorer chilton User Manual

							Lock the flywheel in place and remove the retaining bolts ...
Remove the flywheel attaching bolts and remove the flywheel.
3. 
... then remove the flywheel from the crankshaft
To install:
Position the flywheel on the crankshaft flange. Coat the threads of the flywheel attaching bolts with
Loctite® or equivalent and install the bolts. Tighten the bolts in sequence across from each other to
specifications.
4.  HOW TO USE THIS BOOK
434 REMOVAL & INSTALLATION 
						

							Upon installation, apply a thread-locking compound to the flywheel bolts
On a manual shift transmission, install the clutch disc and pressure plate and cover assembly
following the procedures in Section 7.
5. 
Install the transmission following the procedure in Section 7.
6. 
Chilton® Automotive Information Systems. © 2004 Thomson Delmar Learning. HOW TO USE THIS BOOK
REMOVAL & INSTALLATION 435 
						

							
EXHAUST SYSTEM
Safety glasses should be worn at all times when working on or near the exhaust system. Older exhaust
systems will almost always be covered with loose rust particles which are more than a nuisance and
could injure your eye.
CAUTION
DO NOT perform exhaust repairs or inspection with the engine or exhaust hot. Allow the system to cool
completely. Exhaust systems are noted for sharp edges, flaking metal and rusted bolts. Gloves and eye
protection are required. A healthy supply of penetrating oil and rags is highly recommended.
Cracks in the muffler are a guaranteed leak
EXHAUST SYSTEM 437 
						

							Check the muffler for rotted spot welds and seams
Your vehicle must be raised and supported safely at four points to inspect the exhaust system properly. Start
the inspection at the exhaust manifold where the header pipe is attached and work your way to the back of the
vehicle. On dual exhaust systems, remember to inspect both sides of the vehicle. Check the complete exhaust
system for open seams, holes, loose connections, or other deterioration which could permit exhaust fumes to
seep into the passenger compartment. Inspect all mounting brackets and hangers for deterioration, some may
have rubber O-rings that can become overstretched and non-supportive (and should be replaced if worn).
Many technicians use a pointed tool to poke up into the exhaust system at rust spots to see whether or not they
crumble. Most models have heat shield(s) covering certain parts of the exhaust system, it is often necessary to
remove these shields to visually inspect those components. HOW TO USE THIS BOOK
438 EXHAUST SYSTEM 
						

							Make sure the exhaust does contact the body or suspension
Check for overstretched or torn exhaust hangers HOW TO USE THIS BOOK
EXHAUST SYSTEM 439 
						

							Example of a badly deteriorated exhaust pipe
Inspect flanges for gaskets that have deteriorated and need replacement
Some systems, like this one, use large O-rings (donuts) in between the flanges
REPLACEMENT
There are basically two types of exhaust systems. One is the flange type where the component ends are
attached with bolts and a gasket in-between. The other exhaust system is the slip joint type. These
components slip into one another using clamps to retain them together.
CAUTION
Allow the exhaust system to cool sufficiently before spraying a solvent exhaust fasteners. Some solvents are
highly flammable and could ignite when sprayed on hot exhaust components.
Before removing any component of the exhaust system, ALWAYS squirt a liquid rust dissolving agent onto
the fasteners for ease of removal. A lot of knuckle skin will be saved by following this rule. It may even be
wise to spray the fasteners and allow them to sit overnight. HOW TO USE THIS BOOK
440 REPLACEMENT 
						

							Nuts and bolts will be extremely difficult to remove when deteriorated with rust
CAUTION
Do NOT perform exhaust repairs or inspection with the engine or exhaust hot. Allow the system to cool.
Exhaust systems are noted for sharp edges, flaking metal and rusted bolts. Gloves and eye protection are
required.
Example of a flange type exhaust system jointHOW TO USE THIS BOOK
REPLACEMENT 441 
						

							Example of a common slip joint type system
Raise and support the vehicle safely, as necessary for access. Remember that some longer exhaust
pipes may be difficult to wrestle out from under the vehicle if it is not supported high enough.
1. 
If you havent already, apply a generous amount of penetrating oil or solvent to any rusted fasteners.
2. 
On flange joints, carefully loosen and remove the retainers at the flange. If bolts or nuts are difficult to
break loose, apply more penetrating liquid and give it some additional time to set. If the fasteners still
will not come loose an impact driver may be necessary to jar it loose (and keep the fastener from
breaking).
3. 
When unbolting the headpipe from the manifold, make sure that the bolts are free before trying to
remove them. If you snap a stud in the exhaust manifold, the stud will have to be removed with a bolt
extractor, which often means removal of the manifold itself.
On slip joint components, remove the mounting U-bolts from around the exhaust pipe you are
extracting from the vehicle. Dont be surprised if the U-bolts break while removing the nuts.
4. 
Loosen the exhaust pipe from any mounting brackets retaining it to the floor pan and separate the
components. Slight twisting and turning may be required to remove the component completely from
the vehicle. You may need to tap on the component with a rubber mallet to loosen it. If all else fails,
use a hacksaw to separate the parts. An oxy-acetylene cutting torch may be faster but the sparks are
DANGEROUS near the fuel tank, and at the very least, accidents could happen, resulting in damage
to the under-vehicle parts, not to mention yourself.
5. 
When installing exhaust components, you should loosely position all components before tightening
any of the joints. Once you are certain that the system is run correctly, begin tightening the fasteners
at the front of the vehicle and work your way back.
6. 
Chilton® Automotive Information Systems. © 2004 Thomson Delmar Learning. HOW TO USE THIS BOOK
442 REPLACEMENT 
						

							
ENGINE RECONDITIONING
Determining Engine Condition
Anything that generates heat and/or friction will eventually burn or wear out (for example, a light bulb
generates heat, therefore its life span is limited). With this in mind, a running engine generates tremendous
amounts of both; friction is encountered by the moving and rotating parts inside the engine and heat is created
by friction and combustion of the fuel. However, the engine has systems designed to help reduce the effects of
heat and friction and provide added longevity. The oiling system reduces the amount of friction encountered
by the moving parts inside the engine, while the cooling system reduces heat created by friction and
combustion. If either system is not maintained, a break-down will be inevitable. Therefore, you can see how
regular maintenance can affect the service life of your vehicle. If you do not drain, flush and refill your
cooling system at the proper intervals, deposits will begin to accumulate in the radiator, thereby reducing the
amount of heat it can extract from the coolant. The same applies to your oil and filter; if it is not changed
often enough it becomes laden with contaminates and is unable to properly lubricate the engine. This
increases friction and wear.
There are a number of methods for evaluating the condition of your engine. A compression test can reveal the
condition of your pistons, piston rings, cylinder bores, head gasket(s), valves and valve seats. An oil pressure
test can warn you of possible engine bearing, or oil pump failures. Excessive oil consumption, evidence of oil
in the engine air intake area and/or bluish smoke from the tailpipe may indicate worn piston rings, worn valve
guides and/or valve seals. As a general rule, an engine that uses no more than one quart of oil every 1000
miles is in good condition. Engines that use one quart of oil or more in less than 1000 miles should first be
checked for oil leaks. If any oil leaks are present, have them fixed before determining how much oil is
consumed by the engine, especially if blue smoke is not visible at the tailpipe.
COMPRESSION TEST
A noticeable lack of engine power, excessive oil consumption and/or poor fuel mileage measured over an
extended period are all indicators of internal engine wear. Worn piston rings, scored or worn cylinder bores,
blown head gaskets, sticking or burnt valves, and worn valve seats are all possible culprits. A check of each
cylinders compression will help locate the problem.
A screw-in type compression gauge is more accurate than the type you simply hold against the spark
plug hole.
Although it takes slightly longer to use, its worth the effort to obtain a more accurate reading. Make sure that the proper amount and viscosity of engine oil is in the crankcase, then ensure the
battery is fully charged.
1. 
Warm-up the engine to normal operating temperature, then shut the engine OFF.
2. 
Disable the ignition system.
3. 
Label and disconnect all of the spark plug wires from the plugs.
4. 
Thoroughly clean the cylinder head area around the spark plug ports, then remove the spark plugs.
5. 
Set the throttle plate to the fully open (wide-open throttle) position. You can block the accelerator
linkage open for this, or you can have an assistant fully depress the accelerator pedal.
6. 
ENGINE RECONDITIONING 443 
						

							A screw-in type compression gauge is more accurate and easier to use without an assistant
Install a screw-in type compression gauge into the No. 1 spark plug hole until the fitting is snug.
7. 
WARNING
Be careful not to crossthread the spark plug hole.
According to the tool manufacturers instructions, connect a remote starting switch to the starting
circuit.
8. 
With the ignition switch in the OFFposition, use the remote starting switch to crank the engine
through at least five compression strokes (approximately 5 seconds of cranking) and record the
highest reading on the gauge.
9. 
Repeat the test on each cylinder, cranking the engine approximately the same number of compression
strokes and/or time as the first.
10. 
Compare the highest readings from each cylinder to that of the others. The indicated compression
pressures are considered within specifications if the lowest reading cylinder is within 75 percent of
the pressure recorded for the highest reading cylinder. For example, if your highest reading cylinder
pressure was 150 psi (1034 kPa), then 75 percent of that would be 113 psi (779 kPa). So the lowest
reading cylinder should be no less than 113 psi (779 kPa).
11. 
If a cylinder exhibits an unusually low compression reading, pour a tablespoon of clean engine oil
into the cylinder through the spark plug hole and repeat the compression test. If the compression rises
after adding oil, it means that the cylinders piston rings and/or cylinder bore are damaged or worn. If
the pressure remains low, the valves may not be seating properly (a valve job is needed), or the head
gasket may be blown near that cylinder. If compression in any two adjacent cylinders is low, and if
the addition of oil doesnt help raise compression, there is leakage past the head gasket. Oil and
coolant in the combustion chamber, combined with blue or constant white smoke from the tailpipe,
are symptoms of this problem. However, dont be alarmed by the normal white smoke emitted from
the tailpipe during engine warm-up or from cold weather driving. There may be evidence of water
droplets on the engine dipstick and/or oil droplets in the cooling system if a head gasket is blown.
12. 
OIL PRESSURE TEST
Check for proper oil pressure at the sending unit passage with an externally mounted mechanical oil pressure
gauge (as opposed to relying on a factory installed dash-mounted gauge). A tachometer may also be needed,
as some specifications may require running the engine at a specific rpm. HOW TO USE THIS BOOK
444 COMPRESSION TEST