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(A1) Engine Repair

Animations by ASE Content Area. Includes Tasks and Priority levels.

A: General Engine Diagnosis Tasks (click to expand)

Adjust Valve Clearance (Task 1) (Priority 3)


Task 1: Verify customer concern and/or road test vehicle; determine needed action.

Task 2: Determine if no-cranking, cranks but will not start, or hard starting condition is an engine mechanical problem, or is caused by another vehicle subsystem.

Task 3: Inspect engine assembly for fuel, oil, coolant and other leaks; determine needed action.

Task 4: Isolate engine noises and vibrations; determine needed action.

Task 5: Diagnose the cause of excessive oil consumption, coolant consumption, unusual engine exhaust color and odor; determine needed action.

Task 6: Perform engine manifold vacuum or pressure tests; determine needed action.

Task 7: Perform cylinder power balance tests; determine needed action.

Task 8: Perform cylinder compression tests; determine needed action.

Task 9: Perform cylinder leakage/leak-down tests; determine needed action.

Task 10: Research system operation using technical information to determine service procedures and specifications.

B: Cylinder Head and Valve Train Diagnosis and Repair (click to expand)
Adjust Valve Clearance (Task 1) (Priority 3)


Task 1: Remove cylinder heads, disassemble, clean, and prepare for inspection.

Task 2: Visually inspect cylinder heads for cracks, warpage, corrosion, leakage, and the condition of passages; determine needed repairs.

Task 3: Inspect and repair damaged threads where allowed; install core and gallery plugs.

Task 4: Inspect, test, and verify valve springs for squareness, pressure, and free height comparison; replace as needed.

Task 5: Inspect valve spring retainers, rotators, valve locks, and valve lock grooves.

Task 6: Replace valve stem seals.

Task 7: Inspect valve guides for wear; check valve stem-to-guide clearance; determine needed repairs.

Task 8: Inspect valves and valve seats; determine needed repairs.

Task 9: Check valve spring installed (assembled) height and valve stem height; determine needed repairs.

Task 10: Inspect pushrods, rocker arms, rocker arm pivots, and rocker arm shafts for wear, bending, cracks, looseness, and blocked oil passages; repair or replace as required.

Task 11: Inspect hydraulic or mechanical lifters/lash adjusters; replace as needed.

Task 12: Adjust valves on engines with mechanical or hydraulic lifters.

Task 13: Inspect camshaft drive gear train components (includes gear, chain and belt systems); repair or replace as needed.

Task 14: Inspect and measure camshaft journals and lobes; measure camshaft lift; determine needed repairs.

Task 15: Inspect and measure camshaft bore for wear, damage, out-of-round, and alignment; determine needed repairs.

Task 16: Inspect valve timing; time camshaft(s) to crankshaft.

Task 17: Inspect cylinder head mating surface condition and finish, reassemble and install gasket(s) and cylinder head(s); replace/torque bolts according to manufacturers’ procedures.

Task 18: Inspect overhead camshaft variable valve timing components; repair or replace as needed.

Task 19: Inspect variable valve lift components; repair or replace as needed.

C: Engine Block Diagnosis and Repair (click to expand)
Adjust Valve Clearance (Task 1) (Priority 3)


Task 1: Remove and disassemble engine block; clean, identify selective parts, mark location and orientation, and prepare components for inspection and reassembly.

Task 2: Visually inspect engine block for cracks, corrosion, the condition of passages, core and gallery plug hole condition, surface warpage, and surface finish and condition; inspect piston oil cooling nozzle/jets for damage, proper alignment and restrictions; determine needed action.

Task 3: Inspect and repair damaged threads where allowed; install core and gallery plugs.

Task 4: Clean and inspect cylinder walls; measure cylinder bore; determine needed action.

Task 5: Inspect crankshaft for endplay, journal damage, keyway damage, visual surface cracks, thrust flange and sealing surface condition; check oil passage condition; measure journal wear; check crankshaft reluctor ring/tone wheel (where applicable); determine needed action.

Task 6: Inspect main bearing wear patterns; inspect and measure main bearing bores and cap alignment; mark caps for location and direction; clean and inspect crankshaft girdle (bed plate/ladder) where applicable.

Task 7: Install main bearings and crankshaft; check bearing clearances and endplay; inspect, replace and torque bolts according to manufacturer’s procedures.

Task 8: Inspect camshaft bearings for excessive wear and alignment; replace bearings if necessary; install camshaft, timing chain and gears; check endplay.

Task 9: Inspect auxiliary (balance, intermediate, idler, counterbalance or silencer) shaft(s), drive(s)/gear(s), chain(s), and support bearings for damage and wear; time balance shaft to crankshaft; determine needed action.

Task 10: Inspect, measure, service or replace pistons and piston/wrist pins; identify piston and bearing wear patterns caused by connecting rod alignment concerns; determine needed action.

Task 11: Inspect connecting rods and bearings for damage, bore condition, and pin fit; mark caps for location and direction; determine needed action.

Task 12: Inspect, measure, and install or replace piston rings; assemble piston and connecting rod; install piston/rod assembly; check bearing clearance and sideplay; install connecting rod bearings; inspect, replace and torque fasteners according to manufacturer’s procedures.

Task 13: Inspect, reinstall or replace crankshaft vibration damper/harmonic balancer.

Task 14: Inspect crankshaft flange and flywheel mating surfaces; inspect and replace crankshaft pilot bearing/bushing (if applicable); inspect flywheel/flexplate and flywheel ring gear for cracks and wear (includes dual-mass flywheel); measure flywheel runout; determine needed action.

D: Lubrication and Cooling Systems Diagnosis and Repair (click to expand)
Adjust Valve Clearance (Task 1) (Priority 3)


Task 1: Diagnose engine lubrication system problems; perform oil pressure tests; perform engine oil dye test; determine needed action.

Task 2: Disassemble and inspect oil pump (includes gears, rotors, housing, pick-up assembly and variable displacement components); measure oil pump clearance; inspect pressure relief devices, control systems, and pump drive (includes belt/chain drive); determine needed action.

Task 3: Inspect, flush, and test internal and external engine oil coolers; determine needed action.

Task 4: Change engine oil and filter(s) using proper type, viscosity, and rating per manufacturer’s specifications.

Task 5: Perform cooling system pressure tests; perform coolant dye test; determine needed action.

Task 6: Inspect and test radiator, heater core, pressure cap, and coolant recovery system; replace as required.

Task 7: Inspect, reinstall or replace, and adjust drive belt(s), tensioner(s), and pulleys.

Task 8: Inspect and replace engine cooling system and heater system hoses, pipes, fittings and valves.

Task 9: Inspect, test, reinstall or replace thermostat, coolant by-pass, and thermostat housing (including electronically controlled thermostats).

Task 10: Inspect and replace water pump(s) (including electrical water pumps).

Task 11: Inspect and test coolant; drain, flush, and refill cooling system with recommended coolant; bleed air as required.

Task 12: Inspect and test fan (both electrical and mechanical), fan clutch, fan shroud, air dams, and cooling fan electrical circuits; repair or replace as required.

Task 13: Verify proper operation of engine related warning indicators.

E: Fuel, Electrical, Ignition, and Exhaust Systems Inspection and Service (click to expand)
Adjust Valve Clearance (Task 1) (Priority 3)


Task 1: Inspect, clean or replace fuel injection system components (including gasoline direct injection/GDI), intake manifold, and gaskets.

Task 2: Inspect, service or replace air filters, filter housings, and intake ductwork.

Task 3: Inspect turbocharger/supercharger systems; determine needed action.

Task 4: Test engine cranking system; determine needed repairs.

Task 5: Inspect and test positive crankcase ventilation (PCV) system components; replace as needed.

Task 6: Inspect and test ignition system components; replace as needed.

Task 7: Inspect and diagnose exhaust system; determine needed repairs.