1986 MERCEDES BENZ GENERAL INFORMATION

GENERAL INFORMATION
Trouble Shooting - Basic Procedures
ACCESSORIES & ELECTRICAL

NOTE: This is GENERAL information. This article is not intended to be specific to any unique situation or individual vehicle configuration. The purpose of this Trouble Shooting information is to provide a list of common causes to problem symptoms. For model-specific Trouble Shooting, refer to SUBJECT, DIAGNOSTIC, or TESTING articles available in the section(s) you are accessing.
CHARGING SYSTEM TROUBLE SHOOTING

BASIC CHARGING SYSTEM TROUBLE SHOOTING CHART
CONDITION & POSSIBLE CAUSE CORRECTION
Vehicle Will Not Start
Dead battery Check battery cells, alternator belt tension and alternator output
Loose or corroded battery connections Check all charging system connections
Ignition circuit or switch malfunction Check and replace as necessary
Alternator Light Stays On With Engine Running
Loose or worn alternator drive belt Check alternator drive tension and condition, See Belt Adjustment in TUNE-UP article in the TUNE-UP section
Loose alternator wiring connections Check all charging system connections
Short in alternator light wiring See Indicator Warning Lights in STANDARD INSTRUMENTS in the ACCESSORIES & EQUIPMENT section
Defective alternator stator or diodes See Bench Tests in ALTERNATOR article
Defective regulator See Regulator Check in ALTERNATOR article
Alternator Light Stays Off With Ignition Switch ON
Blown fuse See WIRING DIAGRAMS
Defective alternator See Testing in ALTERNATOR article
Defective indicator light bulb or socket See Indicator Warning Lights in STANDARD INSTRUMENTS in the ACCESSORIES & EQUIPMENT section
Alternator Light Stays OFF With Ignition Switch ON
Short in alternator wiring See On-Vehicle Tests in ALTERNATOR article
Defective rectifier bridge See Bench Tests in ALTERNATOR article
Lights or Fuses Burn Out Frequently
Defective alternator wiring See On-Vehicle Tests in ALTERNATOR article
Defective regulator See Regulator Check in ALTERNATOR article
Defective battery Check and replace as necessary
Ammeter Gauge Shows Discharge
Loose or worn drive belt Check alternator drive belt tension and condition. See Belt Adjustment in TUNE-UP article in the TUNE-UP section
Defective wiring Check all wires and wire connections
Defective alternator or regulator See Bench Tests and On-Vehicle Tests in ALTERNATOR article
Defective ammeter, or improper ammeter wiring connection See Testing in STANDARD INSTRUMENTS in the ACCESSORIES & EQUIPMENT section
Noisy Alternator
Loose drive pulley Tighten drive pulley attaching nut
Loose mounting bolts Tighten all alternator mounting bolts
Worn or dirty bearings See Bearing Replacement ALTERNATOR article
Defective diodes or stator See Bench Test in ALTERNATOR article
Battery Does Stay Charged
Loose or worn drive belt Check alternator drive belt tension and condition. See Belt Adjustment in appropriate TUNE-UP article in the TUNE-UP section
Loose or corroded battery connections Check all charging system connections
Loose alternator connections Check all charging system connections
Defective alternator or battery See On-Vehicle Tests and Bench Tests in ALTERNATOR article
Add-on electrical accessories exceeding alternator capacity Install larger alternator
Battery Overcharged-Uses Too Much Water
Defective battery Check alternator output and repair as necessary
Defective alternator See On-Vehicle Test and Bench Tests in ALTERNATOR article
Excessive alternator voltage Check alternator output and repair as necessary
IGNITION SYSTEM TROUBLE SHOOTING

Fig. 1: Ignition Secondary Trouble Shooting Chart

Fig. 2: Ignition Primary Trouble Shooting Chart
STARTER TROUBLE SHOOTING

BASIC STARTER TROUBLE SHOOTING CHART
CONDITION & POSSIBLE CAUSE CORRECTION
Starter Fails to Operate
Dead battery or bad connections between starter and battery Check battery charge and all wires and connections to starter
Ignition switch faulty or misadjusted Adjust or replace ignition switch
Open circuit between starter switch ignition terminal on starter relay Check and repair wires and connections as necessary
Starter relay or starter defective See Testing in STARTER article
Open solenoid pull-in wire Testing in STARTER article
Starter Does Not Operate and Headlights Dim
Weak battery or dead cell Charge or replace battery as necessary
Loose or corroded battery connections Check that battery connections are clean and tight
Internal ground in starter windings See Testing in STARTER article
Grounded starter fields See Testing in STARTERS
Armature rubbing on pole See STARTER article shoes
Starter Turns but Engine Does Not Rotate
Starter clutch slipping See STARTER article
Broken clutch housing See STARTER article
Pinion shaft rusted or dry See STARTER article
Engine basic timing incorrect See Ignition Timing in TUNE-UP article
Broken teeth on engine flywheel Replace flywheel and check for starter pinion gear damage
Starter Will Not Crank Engine
Faulty overrunning clutch See STARTER article
Broken clutch housing See STARTER article
Broken flywheel teeth Replace flywheel and check for starter pinion gear damage
Armature shaft sheared or reduction gear teeth stripped See STARTER article
Weak battery Charge or replace battery as necessary
Faulty solenoid See On-Vehicle Tests in STARTER article
Poor grounds Check all ground connections for tight and clean connections
Ignition switch faulty or misadjusted Adjust or replace ignition switch as necessary
Starter Cranks Engine Slowly
Battery weak or defective Charge or replace battery as necessary
Engine overheated See ENGINE COOLING SYSTEM article
Engine oil too heavy Check that proper viscosity oil is used
Poor battery-to-starter connections Check that all between battery and starter are clean and tight
Current draw too low or too high See Bench Tests in STARTER article
Bent armature, loose pole shoes screws or worn bearing See STARTER article
Burned solenoid contacts Replace solenoid
Faulty starter Replace starter
Starter Engages Engine Only Momentarily
Engine timing too far advanced See Ignition Timing in TUNE-UP article
Overrunning clutch not engaging properly Replace overrunning clutch. See STARTER article
Broken starter clutch See STARTER article
Broken teeth on engine flywheel Replace flywheel and check starter pinion gear for damage
Weak drive assembly thrust spring See STARTER article
Weak hold-in coil See Bench Tests in STARTER article
Starter Drive Will Not Engage
Defective point assembly See Testing in STARTER article
Poor point assembly ground See Testing in STARTER article
Defective pull-in coil Replace starter solenoid
Starter Relay Does Not Close
Dead battery Charge or replace battery as necessary
Faulty wiring Check all wiring and connections leading to relay
Neutral safety switch faulty Replace neutral safety switch
Starter relay faulty Replace starter relay
Starter Drive Will Not Disengage
Starter motor loose on mountings Tighten starter attach bolts
Worn drive end bushing See STARTER article
Damaged engine flywheel teeth Replace flywheel and starter pinion gear for damage
Drive yolk return spring broken or missing Replace return spring
Faulty ignition switch Replace ignition switch
Insufficient clearance between winding leads to solenoid terminal and main contact in solenoid Replace starter solenoid
Starter clutch not disengaging Replace starter clutch
Ignition starter switch Replace ignition switch contacts sticking
Starter Relay Operates but Solenoid Does Not
Faulty solenoid switch, switch connections or relay Check all wiring between relay and solenoid or replace relay or solenoid as necessary
Broken lead or loose soldered connections Repair wire or wire connections as necessary
Solenoid Plunger Vibrates When Switch is Engaged
Weak battery Charge or replace battery as necessary
Solenoid contacts corroded Clean contacts or replace solenoid
Faulty wiring Check all wiring leading to solenoid
Broken connections inside switch cover Repair connections or replace solenoid
Open hold-in wire solenoid
Low Current Draw
Worn brushes or weak brush springs Replace brushes or brush springs as necessary
High Pitched Whine During Cranking Before Engine Fires but Engine Fires and Cranks Normally
Distance too great between starter pinion and flywheel Align starter or check that correct starter and flywheel are being used
High Pitched Whine After Engine Fires With Key released. Engine Fires and Cranks Normally
Distance too small between starter pinion and flywheel Flywheel runout contributes to the intermittent nature
AIR CONDITIONING & HEAT
AIR CONDITIONING TROUBLE SHOOTING

WARNING: This is GENERAL information. This article is not intended to be specific to any unique situation or individual vehicle configuration. The purpose of this Trouble Shooting information is to provide a list of common causes to problem symptoms. For model-specific Trouble Shooting, refer to SUBJECT, DIAGNOSTIC, or TESTING articles available in the section(s) you are accessing.

BASIC AIR CONDITIONING TROUBLE SHOOTING CHART
CONDITION POSSIBLE CAUSE
Compressor Not Working Compressor clutch circuit open.
..... Compressor clutch coil inoperative.
..... Poor clutch ground connection.
..... Fan belts loose.
..... Thermostatic switch inoperative.
..... Thermostatic switch not adjusted.
..... Ambient temperature switch open.
..... Superheat fuse blown.
Excessive Noise or Vibration Missing or loose mounting bolts.
..... Bad idler pulley bearings.
..... Fan belts not tightened correctly.
..... Compressor clutch contacting body.
..... Excessive system pressure.
..... Compressor oil level low.
..... Damaged clutch bearings.
..... Damaged reed valves.
..... Damaged compressor.
Insufficient or No Cooling; Compressor Working Expansion valve inoperative.
..... Heater control valve stuck open.
..... Low system pressure.
..... Blocked condenser fins.
..... Blocked evaporator fins.
..... Vacuum system leak.
..... Vacuum motors inoperative.
..... Control cables improperly adjusted.
..... Restricted air inlet.
..... Mode doors binding.
..... Blower motor inoperative.
..... Temperature above system capacity.
HEATER SYSTEM TROUBLE SHOOTING

NOTE: This is GENERAL information. This article is not intended to be specific to any unique situation or individual vehicle configuration. The purpose of this Trouble Shooting information is to provide a list of common causes to problem symptoms. For model-specific Trouble Shooting, refer to DIAGNOSTIC, or TESTING articles available in the section(s) you are accessing.

BASIC HEATER SYSTEM TROUBLE SHOOTING CHART
CONDITION POSSIBLE CAUSE
Insufficient, Erratic, or No Heat Low Coolant Level
..... Incorrect thermostat.
..... Restricted coolant flow through core.
..... Heater hoses plugged.
..... Misadjusted control cable.
..... Sticking heater control valve.
..... Vacuum hose leaking.
..... Vacuum hose blocked.
..... Vacuum motors inoperative.
..... Blocked air inlet.
..... Inoperative heater blower motor.
..... Oil residue on heater core fins.
..... Dirt on heater core fins.
Too Much Heat Improperly adjusted cables.
..... Sticking heater control valve.
..... No vacuum to heater control valve.
..... Temperature door stuck open.
Air Flow Changes During Acceleration Vacuum system leak.
..... Bad check valve or reservoir.
Air From Defroster At All Times Vacuum system leak.
..... Improperly adjusted control cables.
..... Inoperative vacuum motor.
Blower Does Not Operate Correctly Blown fuse.
..... Blower motor windings open.
..... Resistors burned out.
..... Motor ground connection loose.
..... Wiring harness connections loose.
..... Blower motor switch inoperative.
..... Blower relay inoperative.
..... Fan binding or foreign object in housing.
..... Fan blades broken or bent.
BRAKES
BRAKE SYSTEM TROUBLE SHOOTING

BRAKE SYSTEM TROUBLE SHOOTING CHART
CONDITION & POSSIBLE CAUSE CORRECTION
Brakes Pull Left or Right
Incorrect tire pressure Inflate tires to proper pressure
Front end out of alignment See WHEEL ALIGNMENT
Mismatched tires Check tires sizes
Restricted brake lines or hoses Check hose routing
Loose or malfunctioning caliper See DISC BRAKES or BRAKE SYSTEM
Bent shoe or oily linings See DRUM BRAKES or BRAKE SYSTEM
Malfunctioning rear brakes See DRUM, DISC BRAKES or BRAKE SYSTEM
Loose suspension parts See SUSPENSION
Noises Without Brakes Applied
Front linings worn out Replace linings
Dust or oil on drums or rotors See DRUM, DISC BRAKES or BRAKE SYSTEM
Noises With Brakes Applied
Insulator on outboard shoe damaged See DISC BRAKES or BRAKE SYSTEM
Incorrect pads or linings Replace pads or linings
Brake Rough, Chatters or Pulsates
Excessive lateral runout Check rotor runout
Parallelism not to specifications Reface or replace rotor
Wheel bearings not adjusted See SUSPENSION
Rear drums out-of-round Reface or replace drums
Disc pad reversed, steel against rotor Remove and reinstall pad
Excessive Pedal Effort
Malfunctioning power unit See POWER BRAKES or BRAKE SYSTEM
Partial system failure Check fluid and pipes
Worn disc pad or lining Replace pad or lining
Caliper piston stuck or sluggish See DISC BRAKES or BRAKE SYSTEM
Master cylinder piston stuck See MASTER CYLINDERS or BRAKE SYSTEM
Brake fade due to incorrect pads for linings Replace pads or linings
Linings or pads glazed Replace pads or linings
Worn drums Reface or replace drums
Excessive Pedal Travel
Partial brake system failure Check fluid and pipes
Insufficient fluid in master cylinder See MASTER CYLINDERS or BRAKE SYSTEM
Air trapped in system See BRAKE BLEEDING or BRAKE SYSTEM
Rear brakes not adjusted See Adjustments in DRUM BRAKES or BRAKE SYSTEM
Bent shoe or lining See DRUM BRAKES or BRAKE SYSTEM
Plugged master cylinder cap See MASTER CYLINDERS or BRAKE SYSTEM
Improper brake fluid Replace brake fluid
Pedal Travel Decreasing
Compensating port plugged See MASTER CYLINDERS or BRAKE SYSTEM
Swollen cup in master cylinder See MASTER CYLINDERS or BRAKE SYSTEM
Master cylinder piston not returning See MASTER CYLINDERS or BRAKE SYSTEM
Weak shoe retracting springs See DRUM BRAKES BRAKE SYSTEM
Wheel cylinder piston sticking See DRUM BRAKES or BRAKE SYSTEM
Dragging Brakes
Master cylinder pistons not returning See MASTER CYLINDERS BRAKE SYSTEM
Restricted brake lines or hoses Check line routing
Incorrect parking brake adjustment See DRUM BRAKES BRAKE SYSTEM
Parking Brake cables frozen See DRUM BRAKES BRAKE SYSTEM
Incorrect installation of inboard disc pad Remove and replace correctly
Power booster output rod too long See POWER BRAKE UNITS BRAKE SYSTEM
Brake pedal not returning freely See DISC, DRUM BRAKES BRAKE SYSTEM
Brakes Grab or Uneven Braking Action
Malfunction of combination valve See CONTROL VALVE or BRAKE SYSTEM
Malfunction of power brake unit See POWER BRAKE UNITS or BRAKE SYSTEM
Binding brake pedal See DISC, DRUM BRAKES or BRAKE SYSTEM
Pulsation or Roughness
Uneven pad wear caused by caliper See DISC BRAKES or BRAKE SYSTEM
Uneven rotor wear See DISC BRAKES or BRAKE SYSTEM
Drums out-of-round Reface or replace drums
ENGINE MECHANICAL
COOLING SYSTEM TROUBLE SHOOTING

COOLING SYSTEM TROUBLE SHOOTING
CONDITION & POSSIBLE CAUSE CORRECTION
Overheating
Coolant Leak Fill/Pressure Test System
A/C Condenser Fins Clogged Remove/Clean Condenser
Radiator Fins Clogged Remove/Clean Radiator
Thermostat Stuck Closed Replace Thermostat
Clogged Cooling System Passages Clean/Flush Cooling System
Water Pump Malfunction Replace Water Pump
Fan Clutch Malfunction Replace Fan Clutch
Retarded Ignition Timing Reset Ignition Timing
Cooling Fan Malfunction Test Cooling Fan/Circuit
Cooling Fan Motor Malfunction Test Fan Motor
Cooling Fan Relay Malfunction Test Fan Relay
Faulty Radiator Cap Replace Radiator Cap
Broken/Slipping Fan Belt Replace Fan Belt
Restricted Exhaust Repair Exhaust System
Corrosion
Impurities In Coolant Clean/Flush System
Coolant Leakage
Damaged hose Replace Hose
Leaky Water Pump Replace Water Pump
Damaged Radiator Seam Replace/Repair Radiator
Leaky Thermostat Cover Replace Thermostat Cover
Cylinder Head Problem Check Head/Head Gasket
Leaky Freeze Plugs Replace Freeze Plugs
Recovery System Inoperative
Loose and/or Defective Radiator Cap Replace Radiator Cap
Overflow Tube Clogged and/or Leaking Repair Tube
Recovery Bottle Vent Restricted Clean Vent
No Heater Core Flow
Collapsed Heater Hose Replace Heater Hose
Plugged Heater Core Clean/Replace Heater Core
Faulty Heater Valve Replace Heater Valve
GASOLINE ENGINE - MECHANICAL TROUBLE SHOOTING

BASIC GASOLINE ENGINE - MECHANICAL TROUBLE SHOOTING CHART
CONDITION & POSSIBLE CAUSE CORRECTION
Engine Lopes At Idle
Intake manifold-to-head leaks Replace manifold gasket, See ENGINES
Blown head gasket Replace head gasket, See ENGINES
Worn timing gears, chain or sprocket Replace gears, chain or sprocket
Worn camshaft lobes Replace camshaft, See ENGINES
Overheated engine Check cooling system, See COOLING
Blocked crankcase vent valve Remove restriction
Leaking EGR valve Repair leak and/or replace valve
Faulty fuel pump Replace fuel pump
Engine Has Low Power
Leaking fuel pump Repair leak and/or replace fuel pump
Excessive piston-to-bore clearance Install larger pistons, See ENGINES
Sticking valves or weak valve springs Check valve train components, See ENGINES
Incorrect valve timing Reset valve timing, See ENGINES
Worn camshaft lobes Replace camshaft, See ENGINES
Blown head gasket Replace head gasket. See ENGINES.
Clutch slipping Adjust pedal and/or replace components, See ENGINES
Engine overheating Check cooling system, See COOLING
Auto. Trans. pressure regulator valve faulty Replace pressure regulator valve
Auto. Trans. fluid level too low Add fluid as necessary
Improper vacuum diverter valve operation Replace vacuum diverter valve
Vacuum leaks Inspect vacuum system and repair as required
Leaking piston rings Replace piston rings, See ENGINES
Faulty High Speed Operation
Low fuel pump volume Replace fuel pump
Leaking valves or worn Replace valves and/or springs, See ENGINES
Incorrect valve timing Reset valve timing,See ENGINES
Intake manifold restricted Remove restriction
Worn distributor shaft Replace distributor
Faulty Acceleration
Improper fuel pump stroke Remove pump and reset pump stroke
Incorrect ignition timing Reset ignition timing, See TUNE-UP
Leaking valves Replace valves, See ENGINES
Worn fuel pump diaphragm or piston Replace diaphragm or piston
Intake Backfire
Improper ignition timing Reset ignition timing, See TUNE-UP
Faulty accelerator pump discharge Replace accelerator pump
Improper choke operation Check choke and adjust as required
Defective EGR valve Replace EGR valve
Fuel mixture too lean Reset air/fuel mixture, See TUNE-UP
Choke valve initial clearance too large Reset choke valve initial clearance
Exhaust Backfire
Vacuum leak Inspect and repair vacuum system
Faulty vacuum diverter valve Replace vacuum diverter valve
Faulty choke operation Check choke and adjust as required
Exhaust system leak repair exhaust system leak
Engine Detonation
Ignition timing too far advanced Reset ignition timing, See TUNE-UP
Faulty ignition system Check ignition timing, See TUNE-UP
Spark plugs loose or faulty Retighten or replace plugs
Fuel delivery system clogged Inspect lines, pump and filter for clog
EGR valve inoperative Replace EGR valve
PCV system inoperative Inspect and/or replace hoses or valve
Vacuum leaks Check vacuum system and repair leaks
Excessive combustion chamber deposits Remove built-up deposits
Leaking, sticking or broken valves Inspect and/or replace valves
External Oil Leakage
Fuel pump improperly seated or worn gasket Remove pump, replace gasket and seat properly
Oil pan gasket broken or pan bent Straighten pan and replace gasket
Timing chain cover gasket broken Replace timing chain cover gasket
Rear main oil seal worn Replace rear main oil seal
Oil pan drain plug not seated properly Remove and reinstall drain plug
Camshaft bearing drain hole blocked Remove restriction
Oil pressure sending switch leaking Remove and reinstall sending switch
Excessive Oil Consumption
Worn valve stems or guides Replace stems or guides, See ENGINES
Valve "O" ring seals damaged Replace "O" ring seals, See ENGINES
Plugged oil drain back holes Remove restrictions
Improper PCV valve operation Replace PCV valve
Engine oil level too high Remove excess oil
Engine oil too thin Replace thicker oil
Valve stem oil deflectors damaged Replace oil deflectors
Incorrect piston rings Replace piston rings, See ENGINES
Piston ring gaps not staggered Reinstall piston rings, See ENGINES
Insufficient piston ring tension Replace rings, See ENGINES
Piston ring grooves or oil return slots clogged Replace piston rings, See ENGINES
Piston rings sticking in grooves Replace piston rings, See ENGINES
Piston ring grooves excessively worn Replace piston and rings, See ENGINES
Compression rings installed upside down Replace compression rings correctly, See ENGINES
Worn or scored cylinder walls Rebore cylinders or replace block
Mismatched oil ring expander and rail Replace oil ring expander and rail, See ENGINES
Intake gasket dowels too long Replace intake gasket dowels
Excessive main or connecting rod bearing clearance Replace main or connecting rod bearings, See ENGINES
No Oil Pressure
Low oil level Add oil to proper level
Oil pressure sender or gauge broken Replace sender or gauge
Oil pump malfunction Remove and overhaul oil pump, See ENGINES
Oil pressure relief valve sticking Remove and reinstall valve
Oil pump passages blocked Overhaul oil pump, See ENGINES
Oil pickup screen or tube blocked Remove restriction
Loose oil inlet tube Tighten oil inlet tube
Loose camshaft bearings Replace camshaft bearings, See ENGINES
Internal leakage at oil passages Replace block or cylinder head
Low Oil Pressure
Low engine oil level Add oil to proper level
Engine oil too thin Remove and replace with thicker oil
Excessive oil pump clearance Reduce oil pump clearance, See ENGINES
Oil pickup tube or screen blocked Remove restrictions
Main, rod or cam bearing clearance excessive Replace bearing to reduce clearance, See ENGINES
High Oil Pressure
Improper grade of oil Replace with proper oil
Oil pressure relief valve stuck closed Eliminate binding
Oil pressure sender or gauge faulty Replace sender or gauge
Noisy Main Bearings
Inadequate oil supply Check oil delivery to main bearings
Excessive main bearing clearance Replace main bearings, See ENGINES
Excessive crankshaft end play Replace crankshaft, See ENGINES
Loose flywheel or torque converter Tighten attaching bolts
Loose or damaged vibration damper Tighten or replace vibration damper
Crankshaft journals out-of-round Re-grind crankshaft journals
Excessive belt tension Loosen belt tension
Noisy Connecting Rods
Excessive bearing clearance or missing bearing Replace bearing, See ENGINES
Crankshaft rod journal out-of-round Re-grind crankshaft journal
Misaligned connecting rod or cap Remove rod or cap and realign
Incorrectly tightened rod bolts Remove and re-tighten rod bolts
Noisy Pistons and Rings
Excessive piston-to-bore clearance Install larger pistons, See ENGINES
Bore tapered or out-of-round Rebore block
Piston ring broken Replace piston rings, See ENGINES
Piston pin loose or seized Replace piston pin, See ENGINES
Connecting rods misaligned Realign connecting rods
Ring side clearance too loose or tight Replace with larger or smaller rings
Carbon build-up on piston Remove carbon
Noisy Valve Train
Worn or bent push rods Replace push rods, See ENGINES
Worn rocker arms or bridged pivots Replace push rods, See ENGINES
Dirt or chips in valve lifters Remove lifters and remove dirt/chips
Excessive valve lifter leak-down Replace valve lifters, See ENGINES
Valve lifter face worn Replace valve lifters, See ENGINES
Broken or cocked valve springs Replace or reposition springs
Too much valve stem-to-guide clearance Replace valve guides, See ENGINES
Valve bent Replace valve, See ENGINES
Loose rocker arms Retighten rocker arms, See ENGINES
Excessive valve seat run-out Reface valve seats, See ENGINES
Missing valve lock Install new valve lock
Excessively worn camshaft lobes Replace camshaft, See ENGINES
Plugged valve lifter oil holes Eliminate restriction or replace lifter
Faulty valve lifter check ball Replace lifter check ball, See ENGINES
Rocker arm nut installed upside down Remove and reinstall correctly
Valve lifter incorrect for engine Remove and replace valve lifters
Faulty push rod seat or lifter plunger Replace plunger or push rod
Noisy Valves
Improper valve lash Re-adjust valve lash, See ENGINES
Worn or dirty valve lifters Clean and/or replace lifters
Worn valve guides Replace valve guides, See ENGINES
Excessive valve seat or face run-out Reface seats or valve face
Worn camshaft lobes Replace camshaft, See ENGINES
Loose rocker arm studs Re-tighten rocker arm studs, See ENGINES
Bent push rods Replace push rods, See ENGINES
Broken valve springs Replace valve springs, See ENGINES
Burned,Sticking or Broken Valves
Weak valve springs or warped valves Replace valves and/or springs, See ENGINES
Improper lifter clearance Re-adjust clearance or replace lifters
Worn guides or improper guide clearance Replace valve guides, See ENGINES
Out-of-round valve seats or improper seat width Re-grind valve seats
Gum deposits on valve stems, seats or guide Remove deposits
Improper spark timing Re-adjust spark timing
Broken Pistons/Rings
Undersize pistons Replace with larger pistons, See ENGINES
Wrong piston rings Replace with correct rings, See ENGINES
Out-of-round cylinder bore Re-bore cylinder bore
Improper connecting rod alignment Remove and realign connecting rods
Excessively worn ring grooves Replace pistons, See ENGINES
Improperly assembled piston pins Re-assemble pin-to-piston, See ENGINES
Insufficient ring gap clearance Install new rings, See ENGINES
Engine overheating Check cooling system
Incorrect ignition timing Re-adjust ignition timing, See TUNE-UP
Excessive Exhaust Noise
Leaks at manifold to head, or to pipe Replace manifold or pipe gasket
Exhaust manifold cracked or broken Replace exhaust manifold, See ENGINES