overheating MITSUBISHI DIAMANTE 1900 Repair Manual

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1-2 GENERALINFORMATIONAND MAINTENANCE
Chitton’s Total Car Care manual for the 199M10
Mitsubishi Mirage, Galant and Diamante is intended
to help you learn more about the inner workings of
your vehicle while saving you money on its upkeep
and operation.
The beginning of the book will likely be referred to
the most, since that is where you will find information
for maintenance and tune-up. The other sections deal
with the more complex systems of your vehicle. Oper-
ating systems from engine through brakes are cov-
ered to the extent that the average do-it-yourselfer be-
comes mechanically involved. This book will not
explain such things as rebuilding a differential for the
simple reason that the expertise required and the in-
vestment in special tools make this task uneconomi-
cal. It will, however, give you detailed instructions to
help you change your own brake pads and shoes, re-
place spark plugs, and perform many more jobs that
can save you money, give you personal satisfaction
and help you avoid expensive problems.
A secondary purpose of this book is a reference for
owners who want to understand their vehicle and/or
their mechanics better. In this case, no tools at all are
required.
Before removing any bolts, read through the entire
procedure. This will give you the overall view of what
tools and supplies will be required. There is nothing
more frustrating than having to walk to the bus stop
on Monday morning because you were short one bolt
on Sunday afternoon. So read ahead and plan ahead.
Each operation should be approached logically and
all procedures thoroughly understood before attempt-
ing any work.
All sections contain adjustments, maintenance, re-
moval and installation procedures, and in some cases,
repair or overhaul procedures. When repair is not con-
sidered practical, we tell you how to remove the part
and then how to install the new or rebuilt replacement.
In this way, you at least save labor costs. “Backyard”
repair of some components is just not practical.
Many procedures in this book require you to “label
and disconnect. . ” a group of lines, hoses or wires.
Don’t be lulled into thinking you can remember where
everything goes-you won’t. If you hook up vacuum
or fuel lines incorrectly, the vehicle may run poorly, if
at all. If you hook up electrical wiring incorrectly, you
may instantly learn a very expensive lesson.
You don’t need to know the official or engineering
name for each hose or line. A piece of masking tape
on the hose and a piece on its fitting will allow you to
assign your own label such as the letter A or a short name. As long as you remember your own code, the
lines can be reconnected by matching similar letters
or names. Do remember that tape will dissolve in
gasolrne or other fluids; if a component is to be
washed or cleaned, use another method of identifica-
tion. A permanent felt-tipped marker or a metal scribe
can be very handy for marking metal parts. Remove
any tape or paper labels after assembly.
It’s necessary to mention the difference between
maintenance and repair Maintenance includes rou-
tine inspections, adjustments, and replacement of
parts which show signs of normal wear Maintenance
compensates for wear or deterioration. Repair implies
that something has broken or is not working. A need
for repair is often caused by lack of maintenance. Ex-
ample, draining and refilling the automatic transaxle
fluid is maintenance recommended by the manufac-
turer at specific mileage intervals. Failure to do this
can shorten the life of the transmission/transaxle, re-
quiring very expensive repairs. While no maintenance
program can prevent items from breaking or wearing
out, a general rule can be stated: MAINTENANCE IS
CHEAPER THAN REPAIR.
Two basic mechanrc’s rules should be mentioned
here. First, whenever the left side of the vehicle or en-
gine is referred to, it is meant to specify the drivers
side. Conversely, the right side of the vehicle means
the passengers side. Second, screws and bolts are
removed by turning counterclockwise, and tightened
by turning clockwrse unless specifically noted.
Safety is always the most important rule. Con-
stantly be aware of the dangers involved in working
on an automobile and take the proper precautions.
See the informatron in this section regarding SER-
VICING YOUR VEHICLE SAFELY and the SAFETY
NOTICE on the acknowledgment page.
Pay attention to the instructions provided. There
are 3 common mistakes in mechanical work:
1. Incorrect order of assembly, disassembly or
adjustment. When taking something apart or putting
it together, performing steps in the wrong order usu-
ally just costs you extra time; however, it CAN break
something. Read the entire procedure before begin-
ning disassembly. Perform everything in the order in
which the instructions say you should, even if you
can’t immedrately see a reason for it. When you’re
taking apart something that is very intricate, you
might want to draw a picture of how it looks when as-
sembled at one point in order to make sure you get everything back in its proper position. We will supply
exploded views whenever possible. When making
adjustments, perform them in the proper order. One
adjustment possibly will affect another.
2. Overtorquing (or undertorquing). While it is
more common for overtorquing to cause damage,
undertorquing may allow a fastener to vibrate loose
causing serious damage. Especially when dealing
with aluminum parts, pay attention to torque specifi-
cations and utilize a torque wrench in assembly. If a
torque figure is not available, remember that if you
are using the right tool to perform the job, you will
probably not have to strain yourself to get a fastener
tight enough. The pitch of most threads is so slight
that the tension you put on the wrench will be multi-
plied many times in actual force on what you are
tightening. A good example of how critical torque is
can be seen in the case of spark plug installation, es-
pecially where you are putting the plug into an alu-
minum cylinder head. Too little torque can fail to
crush the gasket, causing leakage of combustion
gases and consequent overheating of the plug and
engine parts. Too much torque can damage the
threads or distort the plug, changing the spark gap.
There are many commercial products available for
ensuring that fasteners won’t come loose, even if they
are not torqued just right (a very common brand is
Loctite? If you’re worried
about getting something
together tight enough to hold, but loose enough to
avoid mechanical damage during assembly, one of
these products might offer substantial insurance. Be-
fore choosing a threadlocking compound, read the
label on the package and make sure the product is
compatible with the materials, fluids, etc. involved.
3. Crossthreading. This occurs when a part such
as a bolt is screwed into a nut or casting at the wrong
angle and forced. Crossthreading is more likely to
occur if access is difficult. It helps to clean and lubri-
cate fasteners, then to start threading the bolt, spark
plug, etc. with your fingers If you encounter resis-
tance, unscrew the part and start over again at a dif-
ferent angle until it can be inserted and turned several
times without much effort. Keep in mind that many
parts, especially spark plugs, have tapered threads,
so that gentle turning will automatically bring the part
you’re threading to the proper angle. Don’t put a
wrench on the part until its been tightened a couple
of turns by hand. If you suddenly encounter resis-
tance, and the part has not seated fully, don’t force it.
Pull it back out to make sure it’s clean and threading
properly.
Be sure to take your time and be patient, and al-
ways plan ahead. Allow yourself ample time to per-
form repairs and maintenance You may find main-
taining your car a satisfying and enjoyable
experience.
b See Figures 1 thru 15
Naturally, without the proper tools and equipment
it is impossible to properly service your vehicle. It
would also be virtually impossible
to catalog every
tool that you would need to perform all of the opera-
tions in this book. Of course, It would be unwise for
the amateur to rush out and buy an expensive set of
tools on the theory that he/she may need one or more
of them at some time, The best approach is to proceed slowly, gathering savings will
be far outweighed by frustration and
a good quality set of those tools that are used most mangled knuckles.
frequently Don’t be misled by the low cost of bargain Begin accumulating those tools that are used most
tools. It is far better to spend a little more for better frequently: those associated with routine maintenance
quality. Forged wrenches, 6 or 12-point sockets and and tune-up. In addition to the normal assortment of
fine tooth ratchets are by far preferable to their less screwdrivers and pliers, you should have the follow-
expensive counterparts. As any good mechanic can ing tools:
tell you, there are few worse experiences than trying
l Wrenches/sockets and combination open
to work on a vehicle with bad tools. Your monetary end/box end wrenches in sizes from %-% in. or

TROUBLESHOOiNG 11-7
4. Starter motor spins, but does not engage
a. Check the starter motor for a seized or binding pinion gear.
b. Remove the flywheel inspection plate and check for a damaged ring gear.
Gasoline Engines
1. Engine runs poor/y, hesiiates
a. Check the engine ignition system operation and adjust if possible, or replace defective
parts.
b. Check for restricted fuel injectors and replace as necessary.
c. Check the fuel pump output and delivery. Inspect fuel lines for restrictions. If the fuel
pump pressure is below specification, replace the fuel pump.
d. Check the operation of the engine management system and repair as necessary.
2. Enfline lacks power
a. Check the engine’s tune-up status. Note the tune-up specifications and check for items
such as severely worn spark plugs; adjust or replace as needed. On vehicles with
manually adjusted valve clearances, check for tight valves and adjust to specification.
b. Check the air filter and air intake system. Replace the air filter if it is dirty or contami-
nated. Check the fresh air intake system for restrictions or blockage.
c. Check the operation of the engine fuel and ignition management systems. Check the
sensor operation and wiring. Check for low fuel pump pressure and repair or replace
components as necessary.
d. Check the throttle linkage adjustments. Check to make sure the linkage is fully open-
ing the throttle. Replace any worn or defective bushings or linkages.
e. Check for a restricted exhaust system. Check for bent or crimped exhaust pipes, or in-
ternally restricted mufflers or catalytic converters. Compare inlet and outlet tempera-
tures for the converter or muffler. If the inlet is hot, but outlet cold, the component is
restricted.
f. Check for a loose or defective knock sensor. A loose, improperly torqued or defective
knock sensor will decrease spark advance and reduce power. Replace defective knock
sensors and install using the recommended torque specification.
g. Check for engine mechanical conditions such as low compression, worn piston rings,
worn valves, worn camshafts and related parts. An engine which has severe mechani-
cal wear, or has suffered internal mechanical damage must be rebuilt or replaced to re-
store lost power.
h. Check the engine oil level for being overfilled. Adjust the engine’s oil level, or change
the engine oil and filter, and top off to the correct level.
i. Check for an intake manifold or vacuum hose leak. Replace leaking gaskets or worn
vacuum hoses.
j. Check for dragging brakes and replace or repair as necessary.
k. Check tire air pressure and tire wear. Adjust the pressure to the recommended set-
tings. Check the tire wear for possible alignment problems causing increased rolling
resistance, decreased acceleration and increased fuel usage.
I. Check the octane rating of the fuel used during refilling, and use a higher octane rated
fuel.
3. Poor fuel economy
a. Inspect the air filter and check for any air restrictions going into the air filter housing.
Replace the air filter if it is dirty or contaminated.
b. Check the engine for tune-up and related adjustments. Replace worn ignition parts,
check the engine ignition timing and fuel mixture, and set to specifications if possible.
c. Check the tire size, tire wear, alignment and tire pressure. Large tires create more
rolling resistance, smaller tires require more engine speed to maintain a vehicle’s road
speed. Excessive tire wear can be caused by incorrect tire pressure, incorrect wheel
alignment or a suspension problem. All of these conditions create increased rolling
resistance, causing the engine to work harder to accelerate and maintain a vehicle’s
speed.
d. Inspect the brakes for binding or excessive drag. A sticking brake caliper, overly ad-
justed brake shoe, broken brake shoe return spring, or binding parking brake cable or
linkage can create a significant drag, brake wear and loss of fuel economy. Check the
brake system operation and repair as necessary.
4. Engine runs on (diesels) when turned off
a. Check for idle speed set too high and readjust to specification.
b. Check the operation of the idle control valve, and replace if defective.
c. Check the ignition timing and adjust to recommended settings.
Check for defective
sensors or related components and replace if defective.
d. Check for a vacuum leak at the intake manifold or vacuum hose
and replace defective
gaskets or hoses.
e. Check the engine for excessive carbon build-up in the combustion chamber. Use a
recommended decarbonizing fuel additive or disassemble the cylinder head to remove
the carbon.
f. Check the operation of the engine fuel management system and replace defective sen-
sors or control units.
g. Check the engine operating temperature for overheating and repair as necessary. 5. Engine knocks and pinfls during heavy accele/ation, and on steep hills
a. Check the octane rating of the fuel used during refilling, and use a higher octane rated
fuel.
b. Check the ignition timing and adjust to recommended settings. Check for defective
sensors or related components and replace if defective.
c. Check the engine for excessive carbon build-up in the combustion chamber. Use a
recommended decarbonizing fuel additive or disassemble the cylinder head to remove
the carbon.
d. Check the spark plugs for the correct type, electrode gap and heat range. Replace worn
or damaged spark plugs. For severe or continuous high speed use, install a spark plug
that is one heat range colder.
e. Check the operation of the engine fuel management system and replace defective sen-
sors or control units.
f. Check for a restricted exhaust system. Check for bent or crimped exhaust pipes, or in-
ternally restricted mufflers or catalytic converters. Compare inlet and outlet tempera-
tures for the converter or muffler. If the inlet is hot, but outlet cold, the component is
restricted.
6. Engine atxelerates, but vehicle does not gain speed
a. On manual transmission vehicles, check for causes of a slipping clutch. Refer to the
clutch troubleshooting section for additional information.
b. On automatic transmission vehicles, check for a slipping transmission” Check the
transmission fluid level and condition. If the fluid level is too high, adjust to the cor-
rect level. If the fluid level is low, top off using the recommended fluid type. If the fluid
exhibits a burning odor, the transmission has been slipping internally. Changing the
fluid and filter may help temporarily, however in this situation a transmission may re-
quire overhauling to ensure long-term reliability.
Diesel Engines
1. Engine runs pOOr!y a. Check the injection pump timing and adjust to specification.
b. Check for air in the fuel lines or leaks, and bleed the air from the fuel system.
c. Check the fuel filter, fuel feed and return lines for a restriction and repair as necessary.
d. Check the fuel for contamination, drain and flush the fuel tank and replenish with fresh
fuel.
2. Enfline lacks power
a. Inspect the air intake system and air filter for restrictions and, if necessary, replace the
air filter.
b. Verify the injection pump timing and reset if out of specification.
c. Check the exhaust for an internal restriction and replace failed parts.
d. Check for a restricted fuel filter and, if restricted, replace the filter.
e. Inspect the fuel filler cap vent. When removing the filler cap, listen for excessive hiss-
ing noises indicating a blockage in the fuel filler cap vents, If the filler cap vents are
blocked, replace the cap.
f. Check the fuel system for restrictions and repair as necessary.
g. Check for low engine compression and inspect for external leakage at the glow plugs
or nozzles. If no external leakage is noted, repair or replace the engine.
ENGINE PERFORMANCE TROUBLESHOOTING HINTS When troubleshooting an engine running or performance condition, the mechanical
condition of the engine should be determined before lengthy troubleshooting procedures
are performed.
The engine fuel management systems in fuel injected vehicles rely on electronic sen-
sors to provide information to the engine control unit for precise fuel metering. Unlike
carburetors, which use the incoming air speed to draw fuel through the fuel metering jets
in order to provide a proper fuel-to-air ratio, a fuel injection system provides a specific
amount of fuel which is introduced by the fuel injectors into the intake manifold or intake
port, based on the information provided by electronic sensors.
The sensors monitor the engine’s operating temperature, ambient temperature and the
amount of air entering the engine, engine speed and throttle position to provide informa-
tion to the engine control unit, which, in turn, operates the fuel injectors by electrical
pulses. The sensors provide information to the engine control unit using low voltage
electrical signals. As a result, an unplugged sensor or a poor electrical contact could
cause a poor running condition similar to a failed sensor.
When troubleshooting a fuel related engine condition on fuel injected vehicles, care-
fully inspect the wiring and electrical connectors to the related components. Make sure
the electrical connectors are fully connected, clean and not physically damaged. If neces-
sary, clean the electrical contacts using electrical contact cleaner. The use of cleaning
agents not specifically designed for electrical contacts should not be used, as they could
leave a surface film or damage the insulation of the wiring.
The engine electrical system provides the necessary electrical power to operate the ve-
hicle’s electrical accessories, electronic control units and sensors. Because engine man-
agement systems are sensitive to voltage changes, an alternator which over or under-
charges could cause engine running problems or component failure. Most alternators
utilize internal voltage regulators which cannot be adjusted and must be replaced indi-
vidually or as a unit with the alternator.

TROUBLESHOOTING 11-9
c. On vehicles with electrically controlled cooling fans, check the cooling fan operation.
Check for blown fuses or defective fan motors, temperature sensors and relays, and
replace failed components.
d. Check for a coolant leak caused by a failed head gasket, or a porous water jacket cast-
ing in the cylinder head or engine block. Replace defective parts as necessary.
e. Check for an internally restricted radiator. Flush the radiator or replace if the blockage
is too severe for flushing.
f. Check for a damaged water pump. If coolant circulation is poor, check for a loose wa-
ter pump impeller. If the impeller is loose, replace the water pump.
2. Engine loses coolant
a. Pressure test the cooling system and radiator cap for leaks. Check for seepage caused
by loose hose clamps, failed coolant hoses, and cooling system components such as
the heater control valve, heater core, radiator, radiator cap, and water pump. Replace
defective parts and fill the cooling system with the recommended coolant mixture.
b. Check for a coolant leak caused by a failed head gasket, or a porous water jacket cast-
ing in the cylinder head or engine block. Replace defective parts as necessary.
3. Engine temperature remains co/d when driving
a. Check the thermostat operation. Replace the thermostat if it sticks in the open posi-
tion.
b. On vehicles with electrically controlled cooling fans, check the cooling fan operation.
Check for defective temperature sensors and stuck relays, and replace failed compo-
nents.
c. Check temperature gauge operation if equipped to verify proper operation of the
gauge. Check the sensors and wiring for defects, and repair or replace defective com-
ponents.
4. Engine runs hot
a. Check for an internally restricted radiator. Flush the radiator or replace if the blockage
is too severe for flushing.
b. Check for a loose or slipping water pump drive belt. Inspect the drive belt condition.
Replace the belt if brittle, cracked or damaged. Check the pulley condition and prop-
erly tension the belt.
c. Check the cooling fan operation. Replace defective fan motors, sensors or relays as
necessary.
d. Check temperature gauge operation if equipped to verify proper operation of the
gauge. Check the sensors and wiring for defects, and repair or replace defective com-
ponents.
e. Check the coolant level. Set the heater temperature to full hot, check for internal air
pockets, bleed the cooling system and inspect for leakage. Top off the cooling system
with the correct coolant mixture. Once the engine is cool, recheck the fluid level and
top off as needed.
NOTE: The engine cooling system can also be affected by an engine’s me-
chanical condition. A failed head gasket or a porous casting in the engine
block or cylinder head could cause a loss of coolant and result in engine
overheating.
Some cooling systems rely on electrically driven cooling fans to cool the radiator and
use electrical temperature sensors and relays to operate the cooling fan. When diagnos-
ing these systems, check for blown fuses, damaged wires and verify that the electrical
connections are fully connected, clean and not physically damaged. If necessary, clean
the electrical contacts using electrical contact cleaner. The use of cleaning igents not specifically designed for electrical contacts could leave a film or damage the insulation of
the wiring.
1. Exhaust rattles at idle speed
a. Check the engine and transmission mounts and replace mounts showing signs of
damage or wear.
b. Check the exhaust hangers, brackets and mounts. Replace broken, missing or dam-
aged mounts.
c. Check for internal damage to mufflers and catalytic converters. The broken pieces from
the defective component may travel in the direction of the exhaust flow and collect
and/or create a blockage in a component other than the one which failed, causing en-
gine running and stalling problems. Another symptom of a restricted exhaust is low
engine manifold vacuum. Remove the exhaust system and carefully remove any loose
or broken pieces, then replace any failed or damaged parts as necessary.
d. Check the exhaust system clearance, routing and alignment. If the exhaust is making
contact with the vehicle in any manner, loosen and reposition the exhaust system.
2. Exhaust system vibrates when driving
a. Check the exhaust hangers, brackets and mounts. Replace broken, missing or dam-
aged mounts.
b. Check the exhaust system clearance, routing and alignment. If the exhaust is making
contact with the vehicle in any manner, check for bent or damaged components and
replace, then loosen and reposition the exhaust system.
c. Check for internal damage to mufflers and catalytic converters. The broken pieces from
the defective component may travel in the direction of the exhaust flow and collect
and/or create a blockage in a component other than the one which failed, causing en-
gine running and stalling problems. Another symptom of a restricted exhaust is low
engine manifold vacuum. Remove the exhaust system and carefully remove any loose
or broken pieces, then replace any failed or damaged parts as necessary.
3. Exhaust system hangs too low
a. Check the exhaust hangers, brackets and mounts. Replace broken, missing or dam-
aged mounts.
b. Check the exhaust routing and alignment. Check and replace bent or damaged com-
ponents. If the exhaust is not routed properly, loosen and reposition the exhaust sys-
tern.
4. Exhaust sounds loud
a. Check the system for looseness and leaks. Check the exhaust pipes, clamps, flange
bolts and manifold fasteners for tightness. Check and replace any failed gaskets.
b. Check and replace exhaust silencers that have a loss of efficiency due to internally
broken baffles or worn packing material.
c. Check for missing mufflers and silencers that have been replaced with straight pipes
or with non-original equipment silencers.
NOTE: Exhaust system rattles, vibration and proper alignment should not
be overlooked. Excessive vibration caused by collapsed engine mounts,
damaged or missing exhaust hangers and misalignment may cause surface
cracks and broken welds, creating exhaust leaks or internal damage to ex-
haust components such as the catalytic converter, creating a restriction to
exhaust flow and loss of power.
1. Transmission shit& erratically
a. Check and if not within the recommended range, add or remove transmission fluid to
obtain the correct fluid level. Always use the recommended fluid type when adding
transmission fluid.
b. Check the fluid level condition. If the fluid has become contaminated, fatigued from
excessive heat or exhibits a burning odor, change the transmission fluid and filter us-
ing the recommended type and amount of fluid. A fluid which exhibits a burning odor
indicates that the transmission has been slipping internally and may require future re-
pairs.
c. Check for an improperly installed transmission filter, or missing filter gasket, and re-
pair as necessary.
d. Check for loose or leaking gaskets, pressure lines and fittings, and repair or replace as
necessary.
e. Check for loose or disconnected shift and throttle linkages or vacuum hoses, and re-
pair as necessary. ,
2. Transmission will not engage
a. Check the shift linkage for looseness, wear and proper adjustment, and repair as nec-
essary. b. Check for a loss of transmission fluid and top off as needed with the recommended
fluid.
c. If the transmission does not engage with the shift linkage correctly installed and the
proper fluid level, internal damage has likely occurred, requiring transmission removal
and disassembly.
3. Transmission will not downshift during heavy acceleration
a. On computer controlled transmissions, check for failed sensors or control units and
repair or replace defective components.
b. On vehicles with kickdown linkages or vacuum servos, check for proper linkage ad-
justment or leaking vacuum hoses or servo units.
NOTE: Mlany automatic transmissions use an electronic control module,
electrical sensors and solenoids to control transmission shifting. When
troubleshooting a vehicle with this type of system, be sure the electrical
connectors are fully connected, clean and not physically damaged. If nec-
essary, clean the electrical contacts using electrical contact cleaner. The
use of cleaning agents not specifically designed for electrical contacts
could leave a film or damage the insulation of the wiring.