Cooling System; Excessive Fuel Consumption 2 - Jeep cherokee 1989 Owner's Manual

21 Engine diesels (continues t o run) after being turned off
1
2
lgnition timing incorrect (Chapter 1
3
lncorrect spark plug heat range (Chapter 1).
4 Intake air leak (see Section 8).
5 Carbon build-up in combustion chambers. Remove the cylinder
6 Valves sticking (Chapter 2).
7 Valve clearance incorrect (V6 engine) (Chapter 28).
8
EGR system not operating properly (Chapter 6).
9 Fuel shut-off system not operating properly (Chapter 6).
1 0 Check for causes of overheating (Section 27).
22 Low oil pressure
1 lmproper grade of oil.
2
Oil pump worn or damaged (Chapter 2).
3
Engine overheating (refer to Section 27).
4 Clogged oil filter (Chapter 1).
5
Clogged oil strainer (Chapter 2).
6 Oil pressure gauge not working properly (Chapter 2).
23 Excessive oil consumption
1 Loose oil drain plug.
2 Loose bolts or damaged oil pan gasket (Chapter 2).
3 Loose bolts or damaged front cover gasket (Chapter 2).
4 Front or rear crankshaft oil seal leaking (Chapter 2).
5 Loose bolts or damaged rocker arm cover gasket (Chapter 2).
6 Loose oil filter (Chapter 1
7
Loose or damaged oil pressure switch (Chapter 2).
8 Pistons and cylinders excessively worn (Chapter 2).
9
Piston rings not installed correctly on pistons (Chapter 2).
1 1 Intake and/or exhaust valve oil seals worn or damaged (Chapter 2).
12 Worn valve stems.
13 Worn or damaged valves/guides (Chapter 2).
24 Excessive fuel consumption
1
Dirty or clogged air filter element (Chapter 1
2 lncorrect ~gnition timing (Chapter 1
3 lncorrect idle speed (Chapter 1
4 Low tire pressure or incorrect tire size (Chapter 11
5 Fuel leakage. Check all connections, lines and components in the
fuel system (Chapter 4).
6
Choke not operating properly (Chapter 1
7
Dirty or clogged carburetor jets or fuel injectors (Chapter 4).
25 Fuel odor
1 Fuel leakage. Check all connections, lines and components in the
fuel system (Chapter 4).
2 Fuel tank overfilled. Fill only to automatic shut-off.
3 Charcoal canister filter in Evaporative Emissions Control system
clogged (Chapter 1
4
Vapor leaks from Evaporative Emissions Control system lines
(Chapter 6).
26 Miscellaneous engine noises
1
A strong dull noise that becomes more rapid as the engine accel-
erates indicates worn or damaged crankshaft bearings or an unevenly
The Motor Manual Guy
Troubleshooting
worn crankshaft. To pinpoint the trouble spot, remove the spark plug
wire from one plug at a time and crank the engine over. If the noise
stops, the cylinder with the removed plug wire indicates the problem
area. Replace the bearing and/or service or replace the crankshaft
(Chapter 2).
2 A similar (yet slightly higher pitched) noise to the crankshaft knock-
ing described in the previous paragraph, that becomes more rapid as
the engine accelerates, indicates worn or damaged connecting rod bear-
ings (Chapter 2). The procedure for locating the problem cylinder is
the same as described in Paragraph 1.
3 An overlapping metallic noise that increases in intensity as the
engine speed increases, yet diminishes as the engine warms up in-
dicates abnormal piston and cylinder wear (Chapter 2).To locate the
problem cylinder, use the procedure described in Paragraph 1.
4 A rapid clicking noise that becomes faster as the engine accelerates
indicates a worn piston pin or piston pin hole. This sound will happen
each time the piston hits the highest and lowest points in the stroke
(Chapter 2). The procedure for locating the problem piston is described
in Paragraph 1.
5 A metallic clicking noise coming from the water pump indicates
worn or damaged water pump bearings or pump. Replace the water
pump with a new one (Chapter 3).
6 A rapid tapping sound or clicking sound that becomes faster as
the engine speed increases indicates "valve tapping" or improperly
adjusted valve clearances. This can be identified by holding one end
of a section of hose to your ear and placing the other end at different
spots along the rocker arm cover. The point where the sound is loudest
indicates the problem valve. Adjust the valve clearance (V6 engine)
(Chapter 2B). If the problem persists, you likely have a collapsed valve
lifter or other damaged valve train component. Changing the engine
oil and adding a high viscosity oil treatment will sometimes cure a stuck
lifter problem. If the problem still persists, the lifters, pushrods and
rocker arms must be removed for inspection (see Chapter 2).
7 A steady metallic rattling or rapping sound coming from the area
of the timing chain cover indicates a worn, damaged or out-of-adjust-
ment timing chain. Service or replace the chain and related components
(Chapter 2).

Cooling system

27 Overheating
1
2 Drivebelt defective or not adjusted properly (Chapter 1
3
Radiator core blocked or radiator grille dirty and restricted (Chap-
ter 3).
4 Thermostat faulty (Chapter 3).
5
Fan not functioning properly (Chapter 3).
6
Radiator cap not maintaining proper pressure. Have cap pressure
tested by gas station or repair shop.
7 lgnition timing incorrect (Chapter 1
8 Defective water pump (Chapter 3).
9
lmproper grade of engine oil.
1 0 lnaccurate temperature gauge (Chapter 12).
28
Overcooling
1 Thermostat faulty (Chapter 3).
2 lnaccurate temperature gauge (Chapter 12).
29
External coolant leakage
1
Deteriorated or damaged hoses. Loose clamps at hose connections
(Chapter 1
2
Water pump seals defective. If this is the case, water will drip from
the weep hole in the water pump body (Chapter 3).
Leakage from radiator core or header tank. This will require the
radiator to be professionally repaired (see Chapter 3 for removal
procedures).
4 Engine drain plugs or water jacket freeze plugs leaking (see
0-25