90K Service

Complete 90,000-mile maintenance service including engine oil change, transmission fluid exchange, differential service, spark plug replacement, air filter replacement, cabin filter replacement, brake fluid flush, and multi-point inspection.

Warnings

Tools required

Parts

• Engine oil filter × 1 — ACDelco PF63E or equivalent
• Oil drain plug crush washer × 1 — Use OEM specification
• Spark plugs (iridium) × 8 — ACDelco 41-162 (gap 0.035 inch)
• Engine air filter × 1 — ACDelco A3137C or equivalent
• Cabin air filter × 1 — ACDelco CF3238 or equivalent
• Differential drain plug gasket × 1 — Use OEM specification

Fluids

• ACDelco dexos1 0W-20 — 8.5 qt
• ACDelco Dexron VI ATF — 5 qt
• ACDelco 75W-90 Synthetic Gear Oil — 2 qt
• ACDelco DOT 4 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level ground and engage parking brake. Place wheel chocks behind rear wheels.
2. Allow engine and exhaust system to cool completely (minimum 2 hours).
3. Gather all required fluids, filters, and parts before beginning work.
4. Disconnect negative battery cable to prevent accidental electrical issues during service.
5. Raise front of vehicle with floor jack and support on jack stands at manufacturer-specified jacking points.
6. Remove front wheels and store in safe location.
7. Install oil drain pan under engine oil pan drain plug location.

Procedure

1. 1

   Engine oil and filter change
   Remove oil fill cap on top of engine. Locate oil drain plug on bottom of oil pan and remove using appropriate socket. Allow oil to drain completely (approximately 10 minutes). Remove old crush washer from drain plug and install new crush washer. Reinstall drain plug and torque to specification. Locate oil filter on driver side of engine block, remove using oil filter wrench. Apply thin coat of clean engine oil to new filter gasket. Install new filter hand-tight, then an additional 3/4 turn. Fill engine with 8 quarts of dexos1 0W-20 oil through fill cap. Add remaining 0.5 quarts while checking dipstick to reach proper level.
2. 2

   Automatic transmission fluid partial exchange
   Locate transmission fluid pan on underside of transmission. Place drain pan underneath. Remove transmission pan bolts in crisscross pattern, leaving two bolts slightly tight at one corner. Carefully pry pan down at opposite corner to begin draining fluid. Once fluid slows, remove remaining bolts and lower pan completely. Allow to drain for 10 minutes. Clean pan and magnet of debris. Reinstall pan with new gasket if required, torque bolts to specification. Locate transmission fill plug on passenger side of transmission. Using fluid pump, add 5 quarts of Dexron VI ATF through fill hole. Do not overfill.
3. 3

   Rear differential fluid service
   Locate rear differential on rear axle assembly. Clean area around fill plug (upper) and drain plug (lower). Remove fill plug first to ensure it is not seized. Place drain pan under differential and remove drain plug with drain plug gasket. Allow fluid to drain completely (approximately 15 minutes). Clean magnetic drain plug of metal particles. Install new drain plug gasket and reinstall drain plug. Using fluid pump and fill plug opening, add 2 quarts of 75W-90 synthetic gear oil until fluid reaches bottom of fill plug hole. Reinstall fill plug.
4. 4

   Spark plug replacement
   Open hood and locate ignition coil packs on top of engine (4 per side). Disconnect electrical connector from first coil pack by pressing release tab. Remove coil pack mounting bolt and carefully pull coil straight up to remove. Using spark plug socket and extension, remove old spark plug. Verify new spark plugs are gapped to 0.035 inch. Apply small amount of anti-seize to spark plug threads (avoid electrode area). Install new spark plug hand-tight, then torque to 15 Nm (11 lb-ft) using torque wrench. Reinstall coil pack and torque mounting bolt. Reconnect electrical connector. Repeat process for remaining 7 spark plugs.
5. 5

   Engine air filter replacement
   Locate air filter housing on driver side of engine compartment. Release air box clips on sides of housing. Carefully separate housing top from bottom. Remove old air filter element and inspect housing for debris. Clean housing interior with shop rag if needed. Install new air filter element ensuring proper orientation and seating. Reconnect housing halves and secure all clips.
6. 6

   Cabin air filter replacement
   Open glove box and remove contents. Locate glove box stops on both sides and squeeze inward to lower glove box completely. Locate cabin air filter access door behind glove box. Press release tabs and remove access door. Slide old cabin air filter out, noting direction of airflow arrow. Insert new cabin air filter with airflow arrow pointing in correct direction. Reinstall access door until tabs click into place. Return glove box to normal position.
7. 7

   Brake fluid flush
   Locate brake master cylinder reservoir under hood on driver side. Remove reservoir cap and use turkey baster or fluid pump to remove old brake fluid to minimum line. Refill with fresh DOT 4 brake fluid to MAX line. Starting with right rear wheel, locate brake bleeder valve on caliper. Attach bleeder hose to valve with other end submerged in catch container. Have assistant press brake pedal slowly 3-4 times and hold. Open bleeder valve 1/2 turn, allow fluid to flow until pedal reaches floor, close valve. Repeat until fluid runs clear without air bubbles. Maintain master cylinder level above MIN throughout process. Repeat procedure on left rear, right front, then left front wheel in that order. Top off master cylinder to MAX line when complete.
8. 8

   Multi-point inspection
   Inspect all brake pads and rotors for wear. Measure pad thickness (replace if below 3mm). Check rotors for scoring or excessive wear. Inspect all CV boots and tie rod boots for tears or damage. Check all suspension bushings for cracks or deterioration. Inspect serpentine belt for cracks, glazing, or fraying (replace if needed). Check battery terminals for corrosion and clean if necessary. Inspect all fluid levels including coolant, power steering, and windshield washer. Check tire tread depth on all four tires (replace if below 4/32 inch). Inspect tire sidewalls for damage or bulges. Test operation of all lights including headlights, brake lights, turn signals, and reverse lights.
9. 9

   Reinstall wheels and lower vehicle
   Reinstall front wheels onto hubs ensuring proper seating. Install lug nuts by hand, threading each nut carefully to avoid cross-threading. Using torque wrench, tighten lug nuts in star pattern to specification. Carefully raise vehicle slightly with floor jack and remove jack stands. Lower vehicle completely to ground. Perform final torque check on all lug nuts in star pattern.

Reassembly

1. Reconnect negative battery cable to battery terminal.
2. Ensure all drain plugs, fill plugs, and caps are properly installed and tightened.
3. Verify no tools or parts have been left in engine compartment or under vehicle.
4. Clean up any spilled fluids from undercarriage and engine bay.

Verification

• Start engine and allow to idle. Check for any oil, transmission, or differential leaks around drain plugs and filter.
• Verify oil pressure gauge shows normal pressure within 5 seconds of starting.
• Check all fluid levels with engine at operating temperature and adjust if necessary.
• Test drive vehicle for 5-10 miles, checking transmission shift quality, brake pedal feel, and engine performance.
• After test drive, recheck all fluid levels and inspect for leaks.
• Verify Check Engine Light is not illuminated and no trouble codes are present.
• Reset oil life monitor through Driver Information Center menu (Settings > Vehicle > Oil Life > Reset).
• Document service completion including date, mileage, and any additional findings or recommendations.

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