Tune-Up - Major

Complete major tune-up service including spark plugs, ignition coils, air filter, fuel filter, PCV valve, throttle body cleaning, and engine oil/filter change to restore optimal engine performance and fuel economy.

Warnings

Tools required

Parts

• Spark plugs (AC Delco 41-162) × 8 — AC Delco 41-162 or equivalent iridium
• Ignition coils (if worn) × 8 — AC Delco D581 or equivalent
• Engine air filter × 1 — Use OEM specification
• Engine oil filter × 1 — AC Delco PF48 or equivalent
• PCV valve × 1 — AC Delco CV1151C or equivalent
• Oil drain plug crush washer × 1 — Use OEM specification

Fluids

• ACDelco dexos1 0W-20 — 8.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely (minimum 2 hours after running)
3. Disconnect negative battery terminal and wait 5 minutes
4. Raise front of vehicle and support securely on jack stands
5. Remove engine cover by pulling upward on retaining grommets
6. Gather all tools, parts, and fluids for efficient workflow

Procedure

1. 1

   Remove air intake system
   Disconnect mass airflow sensor electrical connector. Release air box clips and remove intake tube from throttle body. Remove complete air box assembly to access left cylinder bank.
   Torque spec

   Air Box Clips5 Nm (4 lb-ft)
2. 2

   Replace engine air filter
   Open air box housing and remove old air filter element. Inspect housing for debris and clean if necessary. Install new air filter with proper orientation (ribbed side typically faces outward).
3. 3

   Remove ignition coils - right bank (cylinders 2-4-6-8)
   Disconnect electrical connectors from each ignition coil by pressing release tab. Remove single 10mm bolt securing each coil. Pull coils straight up with slight twisting motion to break seal. Label or organize coils by cylinder position.
   Torque spec

   Mounting Bolts34 Nm (25 lb-ft)
4. 4

   Remove spark plugs - right bank
   Use compressed air or shop vacuum to clean debris from spark plug wells before removal. Use spark plug socket with extension to remove all four plugs from right bank. Inspect removed plugs for wear patterns and electrode condition.
5. 5

   Remove ignition coils and spark plugs - left bank (cylinders 1-3-5-7)
   Repeat coil and spark plug removal process for left cylinder bank. Access is improved with air box removed. Clean plug wells thoroughly before removal.
   Torque spec

   Mounting Bolts34 Nm (25 lb-ft)
6. 6

   Install new spark plugs
   Verify new spark plugs are gapped to 0.035 inches (0.9mm) specification. Apply small amount of anti-seize to plug threads (avoid electrode area). Hand-thread each plug carefully to avoid cross-threading. Tighten to 15 lb-ft (20 Nm) - approximately 1/4 turn past finger tight with spark plug socket.
7. 7

   Reinstall or replace ignition coils
   Inspect old coils for cracks, carbon tracking, or boot damage. If replacing, apply dielectric grease inside coil boots. Push coils firmly into spark plug wells ensuring proper seating. Install retaining bolts and reconnect electrical connectors. Ensure connectors click securely.
   Torque spec

   Mounting Bolts34 Nm (25 lb-ft)
8. 8

   Clean throttle body
   Locate throttle body on intake manifold. Disconnect electrical connector from throttle position sensor. Use throttle body cleaner spray and clean shop towels to remove carbon deposits from throttle plate and bore. Do NOT force throttle plate open. Allow to air dry completely before reconnecting.
9. 9

   Replace PCV valve
   Locate PCV valve on driver side valve cover (integrated into cover grommet on L83 engine). Twist and pull to remove old valve. Install new PCV valve by pushing firmly into grommet until seated. Reconnect any associated hoses.
10. 10

    Drain engine oil
    Position drain pan under oil pan drain plug. Remove drain plug using 15mm socket and allow oil to drain completely (approximately 10 minutes). Inspect drain plug and crush washer for damage. Clean drain plug threads and install new crush washer.
    ⚠Used engine oil may be hot. Wear protective gloves and allow adequate draining time.
    Torque spec

    Oil Drain Plug35 Nm (26 lb-ft)
11. 11

    Replace oil filter
    Locate oil filter on driver side of engine block. Use oil filter wrench to remove old filter (oil will drain, position pan accordingly). Clean filter mounting surface on engine block. Apply thin film of clean oil to new filter gasket. Hand-tighten new filter until gasket contacts block, then turn additional 3/4 turn.
12. 12

    Refill engine oil
    Reinstall drain plug with new crush washer and torque properly. Lower vehicle from jack stands. Remove oil fill cap and add 8 quarts of ACDelco dexos1 0W-20 oil using funnel. Install oil fill cap. Start engine and verify oil pressure light extinguishes. Check for leaks at drain plug and filter. Shut off engine, wait 5 minutes, then check oil level and top off to reach full mark on dipstick.
    ℹ️Final oil level check must be performed on level ground with engine off for accurate reading.
    Torque spec

    Oil Drain Plug35 Nm (26 lb-ft)
13. 13

    Reassemble air intake system
    Reinstall air box assembly and secure with clips. Connect intake tube to throttle body ensuring proper seal. Reconnect mass airflow sensor electrical connector. Verify all connections are secure.
    Torque spec

    Air Box Clips5 Nm (4 lb-ft)

Reassembly

1. Reinstall engine cover by aligning grommets and pressing down firmly until seated
2. Reconnect negative battery terminal and torque to specification
3. Verify all electrical connectors are properly seated with audible clicks
4. Confirm no tools or shop towels remain in engine bay

Verification

• Start engine and listen for smooth idle with no misfires or unusual noises
• Allow engine to reach operating temperature and verify no check engine light illumination
• Check for oil leaks around drain plug and filter after 5 minutes of running
• Verify throttle response is crisp with no hesitation during light acceleration
• Scan for diagnostic trouble codes using OBD-II scanner - should show no pending codes
• Test drive vehicle and confirm improved throttle response and smooth power delivery
• Recheck oil level after test drive and top off if necessary
• Reset oil life monitor through driver information center if applicable

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