Engine Removal-Methods And Precautions; Engine-Removal And Installation - Jeep cherokee 1989 Owner's Manual

2D-4
7
Crank the engine over at least seven compression strokes and
watch the gauge. The compression should build up quickly in a healthy
engine. Low compression on the first stroke, followed by gradually in-
creasing pressure on successive strokes, indicates worn piston rings.
A low compression reading on the first stroke, which doesn't build up
during successive strokes, indicates leaking valves or a blown head
gasket (a cracked head could also be the cause). Deposits on the under-
sides of the valve heads can also cause low compression. Record the
highest gauge reading obtained.
8 Repeat the procedure for the remaining cylinders and compare the
results to the Specifications.
9 Add some engine oil (about three squirts from a plunger-type oil
can) to each cylinder, through the spark plug hole, and repeat the test.
1 0 If the compression increases after the oil is added, the piston rings
are definitely worn. If the compression doesn't increase significantly,
the leakage is occurring at the valves or head gasket. Leakage past
the valves may be caused by burned valve seats andlor faces or
warped, cracked or bent valves.
1 1 If t w o adjacent cylinders have equally low compression, there's
a strong possibility that the head gasket between them is blown. The
appearance of coolant in the combustion chambers or the crankcase
would verify this condition.
12 If one cylinder is about 2 0 percent lower than the others, and the
engine has a slightly rough idle, a worn exhaust lobe on the camshaft
could be the cause.
1 3 If the compression is unusually high, the combustion chambers
are probably coated with carbon deposits. If that's the case, the cylinder
1 4 If compression is way down or varies greatly between cylinders,
it would be a good idea to have a leak-down test performed by an
automotive repair shop. This test will pinpoint exactly where the leakage
is occurring and how severe it is.
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4 Engine removal methods and precautions
If you've decided that an engine must be removed for overhaul or
major repair work, several preliminary steps should be taken.
Locating a suitable place to work is extremely important. Adequate
work space, along with storage space for the vehicle, will be needed.
If a shop or garage isn't available, at the very least a flat, level, clean
work surface made of concrete or asphalt is required.
Cleaning the engine compartment and engine before beginning the
removal procedure will help keep your tools and your hands clean.
An engine hoist or A-frame will also be necessary. Make sure the
equipment is rated in excess of the combined weight of the engine
and accessories. Safety is of primary importance, considering the poten-
tial hazards involved i n lifting the engine out of the vehicle.
If the engine is being removed by a novice, a helper should be
available. Advice and aid from someone more experienced would also
be helpful. There are many instances when one person cannot simul-
taneously perform all of the operations required when lifting the engine
out of the vehicle.
Plan the operation ahead of time. Arrange for or obtain all of the tools
and equipment you'll need prior to beginning the job. Some of the equip-
ment necessary to perform engine removal and installation safely and
with relative ease are (in addition to an engine hoist) a heavy duty floor
jack, complete sets of wrenches and sockets as described in the front
of this manual, wooden blocks and plenty of rags and cleaning solvent
for mopping up spilled oil, coolant and gasoline. If the hoist must be
rented, make sure that you arrange for it in advance and perform all
of the operations possible without
money and time.
Plan for the vehicle to be out of use for quite a while. A machine
shop will be required to perform some of the work which the do-it-
yourselfer can't accomplish without special equipment. These shops
often have a busy schedule, so it would be a good idea to consult them
before removing the engine in order to accurately estimate the amount
of time required to rebuild or repair components that may need work.
Always be extremely careful when removing and installing the
engine. Serious injury can result from careless actions. Plan ahead, take
your time and a job of this nature, although major, can be accomplished
successfully.
The Motor Manual Guy
Chapter 2 Part D General engine overhaul procedures
beforehand. This will save you
it
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5 Engine removal and installation
Refer to illustrations 5.5a, 5.5b, 5.52, 5. 1 1, 5. 12, 5.20, 5.24a
and 5.24b
Warning: The air conditioning system is under high pressure! Have a
dealer service department or service station discharge the system
before disconnecting any system hoses or fittings.
Removal
1 Refer t o Chapter 4 and relieve the fuel system pressure (fuel-
injected vehicles only), then disconnect the negative cable from the
battery.
2 Cover the fenders and cowl and remove the hood (see Chapter 1 1
Special pads are available to protect the fenders, but an old bedspread
or blanket will also work.
3 Remove the air cleaner assembly (see Chapter 4).
4 Drain the cooling system (see Chapter 1).
5 Label the vacuum lines, emissions system hoses, wiring connectors,
ground strap and fuel lines, to ensure correct reinstallation (see illustra-
tion), then detach them (see illustrations). If there's any possibility of
Label both ends of each wire before unplugging
the connector
confusion, make a sketch of the engine compartment and clearly label
the lines, hoses and wires.
6 Label and detach all coolant hoses from the engine.
7
Remove the cooling fan, shroud and radiator (see Chapter 3).
8
Remove the drivebelt(s) (see Chapter 1
9 Warning: Gasoline is extremely flammable, so extra precautions
must be taken when working on any part of the fuel system. DO NOT
smoke or allow open flames or bare light bulbs near the vehicle. Also,
don't work in a garage if a natural gas appliance with a pilot light is
present. Disconnect the fuel lines running from the engine t o the chassis
(see Chapter 4). Plug or cap all open fittingsllines.
1 0 Disconnect the throttle linkage (and TV linkagelcruise control cable,
if equipped) from the engine (see Chapter 4).
11 On power steering equipped vehicles, unbolt the power steering
pump (see Chapter 10). Leave the lineslhoses attached (see illustration)
and make sure the pump is kept in an upright position in the engine
compartment (use wire or rope to restrain it out of the way).
12 On air conditioned vehicles, unbolt the compressor (see Chapter 3)
and set it aside. Do not disconnect the hoses (see illustration).
13 Drain the engine oil (see Chapter 1) and remove the oil filter.
1 4 Remove the starter motor (see Chapter 5).
1 5 Remove the alternator (see Chapter 5).