90K Service

Complete 90,000-mile scheduled maintenance service including fluid changes, filter replacements, spark plugs, and comprehensive inspection of wear items and systems.

Warnings

Tools required

Parts

• Engine oil filter × 1 — Use OEM specification
• Air filter × 1 — Use OEM specification
• Spark plugs × 10 — Champion RC12LYC or equivalent
• Fuel filter × 1 — Use OEM specification
• Differential drain plug gasket × 1 — Use OEM specification
• Manual transmission drain plug gasket × 2 — Use OEM specification

Fluids

• 10W-30 conventional engine oil — 11 qt
• Ethylene glycol 50/50 coolant — 24 qt
• 75W-90 GL-5 differential oil with limited-slip additive — 3.5 qt
• Mopar MS-9224 or 75W-90 GL-4 manual transmission fluid — 4.2 qt
• DOT 3 brake fluid — 1 qt

Preparation

1. Park vehicle on level surface and apply parking brake
2. Place wheel chocks behind rear wheels
3. Allow engine, exhaust, and all fluids to cool to ambient temperature (minimum 2 hours)
4. Gather all fluids, filters, and parts before beginning
5. Verify spark plug gap specification (0.035 inch typical for this application) and gap new plugs before installation

Procedure

1. 1

   Raise and support vehicle
   Raise front of vehicle with floor jack at front crossmember. Support on jack stands at manufacturer-designated front lift points. Raise rear of vehicle and support on jack stands at rear differential or frame rails. Verify vehicle is stable before working underneath.
2. 2

   Drain engine oil
   Position drain pan under engine oil pan. Remove oil drain plug from oil pan (located at rear of pan). Allow oil to drain completely (approximately 10-15 minutes; verify exact oil capacity against 1992 Viper service documentation). Inspect drain plug threads and washer; replace washer if damaged. Reinstall drain plug.
3. 3

   Replace oil filter and refill engine oil
   Locate oil filter on driver side of engine block. Remove oil filter using filter wrench. Clean mounting surface on block. Lubricate gasket on new filter with fresh oil. Install new filter hand-tight plus 3/4 turn. Lower vehicle if necessary to access oil filler. Add the factory-specified quantity of engine oil (verify capacity, typically around 8 quarts with filter for the 8.0L V10, against 1992 Viper service documentation) of the factory-recommended viscosity through filler cap. Start engine and check for leaks at filter and drain plug. Shut off engine, wait 5 minutes, check oil level and top off to full mark on dipstick.
4. 4

   Replace air filter
   Open hood and locate air filter housing at front of engine compartment. Release housing clips or fasteners securing air filter cover. Remove old air filter element. Inspect housing for debris and clean if necessary. Install new air filter element ensuring proper seating. Secure housing cover with clips or fasteners.
5. 5

   Replace spark plugs
   Allow engine to cool completely if not already cool. Locate all 10 spark plug wire boots on valve covers (5 per side). Remove spark plug wires one at a time by grasping boot and twisting while pulling. Use spark plug socket and ratchet to remove spark plug from cylinder head. Inspect plug electrode and insulator condition for signs of fouling or damage. Verify new spark plug gap is set to specification. Install new spark plug hand-tight, then torque to the factory specification (do not apply anti-seife unless specified; if used, reduce torque accordingly to avoid damaging aluminum cylinder head threads). Reinstall spark plug wire ensuring boot seats fully. Repeat for all 10 cylinders, working one plug at a time to avoid mixing up wire routing. Note: Use OEM-specified spark plug (verify exact part number against 1992 Viper service documentation)
6. 6

   Drain and refill manual transmission
   With vehicle raised and supported, locate transmission drain plug on underside of transmission case and fill plug on side of case. Remove fill plug first to verify access and prevent draining with no way to refill. Position drain pan under drain plug. Remove drain plug and allow fluid to drain completely. Inspect drain plug gasket and replace. Reinstall drain plug. Using fluid transfer pump, add the factory-specified transmission fluid and capacity (verify fluid type and quantity against 1992 Viper service documentation before filling) through fill hole until fluid reaches the bottom of the fill hole threads. Install fill plug with new gasket.
7. 7

   Drain and refill rear differential
   Position drain pan under rear differential. Remove differential drain plug (located at bottom of differential housing). Allow fluid to drain completely. Remove fill plug from rear of differential housing. Inspect both plug gaskets and replace. Reinstall drain plug with new gasket. Using fluid transfer pump, add the factory-specified quantity of 75W-90 GL-5 gear oil (verify capacity and whether a separate limited-slip additive is required against 1992 Viper service documentation) through fill hole until fluid reaches bottom of fill hole threads. Install fill plug with new gasket.
8. 8

   Replace fuel filter
   Relieve fuel system pressure by removing fuel pump relay (located in power distribution center) and starting engine until it stalls. Locate fuel filter along driver side frame rail between fuel tank and engine. Place drain pan under filter. Disconnect fuel lines from filter by depressing quick-connect tabs or loosening fittings (depending on connection type). Note flow direction arrow on old filter. Remove filter from mounting bracket. Install new filter in bracket with flow arrow pointing toward engine. Connect fuel lines ensuring they lock or seal properly. Reinstall fuel pump relay. Cycle ignition key to ON position (without starting) 3-4 times to pressurize system. Inspect filter connections for leaks before starting engine.
9. 9

   Drain and refill cooling system
   Ensure engine is completely cool. Place large drain pan under radiator. Locate radiator drain petcock at bottom driver side of radiator. Open petcock and allow coolant to drain. Remove radiator cap to speed draining. Once drained, close petcock. Fill cooling system with the factory-specified quantity of 50/50 ethylene glycol coolant mixture (verify capacity against 1992 Viper service documentation) through radiator neck and overflow reservoir. Start engine with radiator cap off and allow to run until thermostat opens (upper radiator hose becomes hot). Add additional coolant as needed to maintain level. Once air is purged and level stabilizes, install radiator cap. Fill overflow reservoir to FULL COLD mark. Run engine to normal operating temperature and check for leaks.
10. 10

    Flush and replace brake fluid
    Locate brake fluid reservoir in engine compartment. Check fluid level and condition. Using turkey baster or fluid suction tool, remove old fluid from reservoir. Refill with fresh DOT 3 brake fluid. Working from furthest wheel from master cylinder to closest (typically RR, LR, RF, LF), attach clear hose to bleeder screw and submerge other end in container with fresh brake fluid. Have assistant pump brake pedal 3-4 times and hold. Open bleeder screw until fluid flows, then close. Repeat until fluid runs clean and clear. Maintain reservoir level throughout process. Repeat for all four wheels. Top off reservoir to MAX line. Test brake pedal for firm feel.
11. 11

    Inspect wear items and systems
    With vehicle raised, inspect the following: brake pads and rotors for remaining thickness and scoring; CV boots and drive axle boots for tears or grease leakage; suspension bushings for cracking or deterioration; shock absorbers for fluid leakage; exhaust system for damage or loose hangers; all visible fluid hoses for cracking, swelling, or seepage; battery terminals for corrosion; serpentine belt for cracking, glazing, or fraying; tire tread depth and sidewalls for damage. Document any components approaching service limits for customer awareness.
12. 12

    Check and adjust tire pressures
    Using accurate tire pressure gauge, check all four tires when cold. Refer to door jamb placard or owner's manual for specified tire pressure (verify exact front and rear pressures against 1992 Viper documentation; front and rear specs likely differ). Adjust as necessary. Inspect tire tread for uneven wear patterns that may indicate alignment issues.
13. 13

    Lower vehicle and perform final checks
    Remove jack stands and carefully lower vehicle to ground. Start engine and verify no warning lights on dash. Check all fluid levels visually one final time: engine oil dipstick, coolant overflow reservoir, brake fluid reservoir, power steering reservoir. Test drive vehicle for 5-10 miles, checking transmission shift quality, brake operation, and watching for any new leaks or warning lights. After test drive, re-inspect all drain plugs, filter, and fill locations for signs of leakage.

Reassembly

1. All drain plugs should be installed with new gaskets where applicable
2. Verify all fill caps are reinstalled: oil filler, coolant cap, brake reservoir, power steering reservoir
3. Double-check that all 10 spark plug wires are properly seated on plugs
4. Ensure air filter housing is fully latched
5. Verify fuel filter connections are locked and not leaking

Verification

• Engine oil level shows FULL on dipstick when checked on level ground after engine has been off for 5+ minutes
• Coolant level is at FULL COLD mark on overflow reservoir when engine is cold
• No fluid leaks visible under vehicle after test drive
• Brake pedal feels firm with no excessive travel
• Engine starts easily and idles smoothly with no misfires
• Transmission shifts smoothly through all gears
• All dashboard warning lights are off during operation
• All tire pressures match specification

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