A1 Engine Repair

  • General Engine Diagnosis
  • Cylinder Head and Valve Train Diagnosis and Repair
  • Engine Block Diagnosis and Repair
  • Lubrication and Cooling Systems Diagnosis and Repair
  • Fuel, Electrical, Ignition, and Exhaust Systems Inspection and Service

Engine Repair

A. General Engine Diagnosis (15 questions)

1. Verify driver’s complaint and/or road test vehicle; determine necessary action.

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

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

4. Isolate engine noises and vibrations; determine necessary action.

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

6. Perform engine vacuum tests; determine necessary action.

7. Perform cylinder power balance tests; determine necessary action.

8. Perform cylinder cranking compression tests; determine necessary action.

9. Perform cylinder leakage tests; determine necessary action.

B. Cylinder Head and Valve Train Diagnosis and Repair (10 questions)

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

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

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

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

5. Inspect valve spring retainers, rotators, locks/keepers, and lock grooves.

6. Replace valve stem seals.

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

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

9. Check valve spring installed (assembled) height and valve stem height; determined needed repairs.

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

11. Inspect and replace hydraulic or mechanical lifters/lash adjusters.

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

13. Inspect and replace camshaft(s) (includes checking drive gear wear and backlash, end play, sprocket and chain wear, overhead cam drive sprocket(s), drive belt(s), belt tension, tensioners, camshaft reluctor ring/tone-wheel, and variable valve timing components).

14. Inspect and measure camshaft journals and lobes; measure camshaft lift.

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

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

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.

C. Engine Block Diagnosis and Repair (10 questions)

1. Remove and disassemble engine block; clean and prepare components for inspection and reassembly.

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; determine necessary action.

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

4. Inspect and measure cylinder walls; hone and clean cylinder walls; determine need for further action.

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

6. Inspect and measure main bearing bores and cap alignment; mark caps for location and direction.

7. Install main bearings and crankshaft; check bearing clearances and end play; replace/torque bolts according to manufacturers’ procedures.

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

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

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

11. Inspect connecting rods for damage, bore condition, and pin fit; determine necessary action.

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; replace/torque fasteners according to manufacturers’ procedures.

13. Inspect, reinstall, or replace crankshaft vibration damper (harmonic balancer).

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

15. Inspect and replace pans and covers.

16. Assemble the engine using gaskets, seals, and formed-in-place (tube-applied) sealants, thread sealers, according to manufacturers’ specifications; reinstall engine.

D. Lubrication and Cooling Systems Diagnosis and Repair (8 questions)

1. Diagnose engine lubrication system problems; perform oil pressure tests; determine necessary action.

2. Disassemble and inspect oil pump (includes gears, rotors, housing, and pick-up assembly); measure oil pump clearance; inspect pressure relief devices and pump drive; determine necessary action.

3. Inspect, test, and replace internal and external engine oil coolers.

4. Fill crankcase with oil and install engine oil filter.

5. Perform cooling system pressure tests; perform coolant dye test; determine necessary action.

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

7. Inspect, replace, and adjust drive belt(s), tensioner(s), and pulleys.

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

9. Inspect, test, and replace thermostat, coolant by-pass, and thermostat housing.

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

11. Inspect and replace water pump.

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.

13. Verify proper operation of engine related warning indicators.

E. Fuel, Electrical, Ignition, and Exhaust Systems Inspection and Service (7 questions)

1. Inspect, clean or replace fuel injection system components, intake manifold, and gaskets.

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

3. Inspect turbocharger/supercharger; determine necessary action.

4. Test engine cranking system; determine needed repairs.

5. Inspect and replace crankcase ventilation system components.

6. Inspect and install ignition system components; adjust timing.

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