LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 2004 >> Thunderbird >> Repair and Diagnosis >> Engine Mechanical >> Mechanical >> Engine System-General Information >> Diagnosis And Testing >> Engine >> Symptom Chart
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Symptom Chart

SYMPTOM SPECIFICATION

Condition Possible Sources Action
  • Difficult starting
  • Inoperative or damaged ignition system.
  • Air or vacuum leak.
  • Inoperative or damaged fuel system.
  • Inoperative or damaged starting system.
  • Damaged charging system/battery.
  • Burnt valve.
  • INSTALL a new valve.
  • Worn piston.
  • Worn piston rings.
  • Worn cylinder.
  • INSTALL a new long block.
  • Damaged head gasket.
  • INSTALL a new cylinder head gasket.
  • Inoperative or damaged cooling system (fail-safe cooling invoked).
  • Poor idling
  • Vacuum leaks.
  • Inoperative or damaged exhaust gas recirculation (EGR) system.
  • Inoperative or damaged variable cam timing (VCT) system.
  • Inoperative or damaged ignition system.
  • Inoperative or damaged cooling system (fail-safe cooling invoked).
  • Inoperative or damaged fuel system.
  • Incorrect valve clearance.
  • Incorrect valve-to-valve seat contact.
  • Instal a new cylinder head.
  • Damaged head gasket.
  • Install a new cylinder head gasket.
  • Abnormal combustion
  • Inoperative or damaged fuel system.
  • Air or vacuum leaks.
  • VCT system fault.
  • EGR system fault.
  • Inoperative or damaged cooling system (fail-safe cooling invoked).
  • Inoperative or damaged ignition system.
  • Burnt or sticking valve.
  • INSTALL a new cylinder head.
  • Weak or broken valve spring.
  • INSTALL a new valve spring.
  • Carbon accumulation in combustion chamber.
  • ELIMINATE carbon buildup.
  • Excessive oil consumption
  • Leaking oil.
  • REPAIR oil leakage.
  • Inoperative PCV system.
  • REPAIR or INSTALL new components as necessary.
  • Incorrect oil.
  • CHANGE oil to correct specification.
  • Worn valve stem seal.
  • INSTALL a new cylinder head.
  • Worn valve stem or valve guide.
  • INSTALL a new cylinder head.
  • Sticking piston rings.
  • Worn piston ring groove.
  • Worn piston or cylinder.
  • INSTALL a new long block.
  • Engine noise
  • Leaking exhaust system.
  • REPAIR exhaust leakage.
  • Incorrect drive belt tension.
  • Worn generator bearing.
  • Worn or damaged coolant pump bearing.
  • Inoperative or damaged cooling system.
  • Inoperative or damaged fuel system.
  • Ignition system knock (spark knock).
  • Inoperative or damaged VCT unit.
  • Inoperative or damaged EGR system.
  • Air leaks.
  • Loose timing chain.
  • INSTALL a new timing chain.
  • Damaged timing chain tensioner.
  • INSTALL a new timing chain tensioner.
  • Excessive main bearing clearance.
  • Seized or heat damaged crankshaft main bearing.
  • Excessive crankshaft end play.
  • Excessive connecting rod bearing clearance.
  • Heat damaged connecting rod bearing.
  • Damaged connecting rod bushing.
  • Worn cylinder.
  • Worn piston or piston pin.
  • Damaged piston rings.
  • Bent connecting rod.
  • INSTALL a new long block.
  • Worn or damaged valve tappet.
  • INSTALL a new valve tappet.
  • Excessive valve tappet clearance.
  • ADJUST clearance or INSTALL a new valve tappet.
  • Broken valve spring.
  • INSTALL a new valve spring.
  • Excessive valve guide clearance.
  • INSTALL a new cylinder head assembly.
  • Insufficient power
  • Inoperative or damaged ignition system.
  • Air intake system blockage.
  • Lubrication system blockage.
  • Electronic throttle control (ETC) system concerns.
  • Inoperative or damaged fuel system.
  • Oil level too high.
  • DRAIN oil to correct level.
  • Incorrect engine oil.
  • INSTALL correct specification engine oil.
  • Excessive accessory drive belt loading.
  • VCT concern
  • Inoperative or damaged cooling system (fail-safe cooling invoked).
  • Damaged or plugged exhaust system.
  • INSPECT exhaust system.
  • Incorrect tire size.
  • Dragging brakes.
  • REFER to DISC article.
  • Slipping transmission.
  • Incorrect valve clearance.
  • Worn or damaged valve tappet.
  • INSTALL a new valve tappet.
  • Damaged valve tappet guide.
  • Compression leakage at valve seat.
  • Seized valve stem.
  • INSTALL a new cylinder head assembly.
  • Weak or broken valve spring.
  • INSTALL a new valve spring.
  • Worn or damaged cam.
  • INSTALL a new camshaft.
  • Damaged head gasket.
  • INSTALL a new head gasket.
  • Cracked or distorted cylinder head.
  • INSTALL a new cylinder head assembly.
  • Damaged, worn or sticking piston ring(s).
  • Worn or damaged piston.
  • INSTALL a new long block.
scientia non olet · About LEMON Manuals