Valve Seals

Replace valve stem seals on the 8.0L V10 engine to correct oil consumption or smoking issues, requiring removal of camshafts and valve train components from both cylinder heads.

Warnings

Tools required

Parts

• Valve stem seal set (intake and exhaust, 20 total) × 1 — Use OEM specification
• Valve cover gaskets (left and right) × 2 — Use OEM specification
• Spark plug tube seals × 10 — Use OEM specification
• Camshaft cap sealant (anaerobic type) × 1 — Mopar or equivalent
• RTV silicone sealant (sensor-safe) × 1 — Use OEM specification
• Engine oil and filter × 1 — 10W-30 conventional
• Throttle body gasket × 1 — Use OEM specification

Fluids

• 10W-30 conventional engine oil — 11 qt

Preparation

1. Ensure engine is fully cool to the touch (minimum 2 hours after last operation).
2. Disconnect negative battery cable and secure away from battery post.
3. Remove engine cover and decorative trim pieces from top of engine.
4. Drain engine coolant into suitable container if accessing coolant passages near cylinder heads.
5. Position vehicle on level surface and engage parking brake. Place wheel chocks at rear wheels.
6. Prepare clean workspace for camshaft and valve train component storage with labeled containers.
7. Have compressed air source with rubber-tipped blow gun adapter ready for valve retention.

Procedure

1. 1

   Remove intake plenum and throttle body assembly
   Disconnect air intake ducting from throttle body. Disconnect throttle cable and cruise control cable from throttle body linkage. Disconnect IAC motor electrical connector and TPS sensor connector. Remove throttle body mounting bolts and set throttle body aside. Disconnect vacuum lines from intake plenum, marking each for reinstallation. Remove the intake plenum mounting bolts (10 bolts total around perimeter) and carefully lift plenum off engine. Inspect and note condition of plenum gasket surfaces.
2. 2

   Remove ignition coil packs and spark plugs
   Disconnect the spark plug wires from the plugs, labeling each for position. The 1992 Viper uses a distributor-based ignition with a single coil and plug wires, not individual coil packs. Using spark plug socket, remove all 10 spark plugs and inspect condition. Store spark plugs in order if reusing for diagnosis. Check spark plug wells for oil accumulation, which indicates failed valve seals or tube seals.
3. 3

   Remove valve covers
   Disconnect any remaining electrical connectors or harness clips attached to valve covers. Remove valve cover bolts (approximately 10 bolts per cover around perimeter). Carefully break valve cover seal using plastic pry tool if necessary, taking care not to damage gasket surfaces. Lift valve covers off cylinder heads and set aside. Remove and discard old valve cover gaskets and spark plug tube seals. Inspect valve train for sludge, varnish, or unusual wear patterns.
4. 4

   Mark and document camshaft positions
   Mark and organize rocker arms and pushrods with their cylinder positions so they can be reinstalled in their original locations. The in-block camshaft is not removed for this job. Take photographs of camshaft timing marks and positions relative to cylinder head. Timing components are not accessed during this valve seal procedure — no camshaft sprocket or timing chain marking is required. This documentation is critical for correct reassembly. Verify engine is at TDC cylinder 1 or mark current crankshaft position with paint mark on harmonic balancer aligned with timing cover reference.
5. 5

   Remove rocker arm assemblies
   This engine is a pushrod OHV design with a single in-block camshaft — there are no rocker shaft assemblies or overhead camshafts to remove. Loosen and remove the individual rocker arm bolts/nuts, then lift off rocker arms and pushrods, keeping all components in exact order for reinstallation.nstallation. Note orientation of oil feed holes in rocker shafts.
6. 6

   Remove camshaft caps and camshafts
   This engine does not have overhead camshafts or camshaft caps in the cylinder heads — the single camshaft is located in the block and does NOT need to be removed for valve seal service. After removing rocker arms and pushdrods, proceed directly to valve spring/seal service on the seated cylinder heads. Inspect cam lobes for scoring, pitting, or excessive wear. Store camshafts on padded surface where they cannot roll. Cover exposed valve train with clean shop towels to prevent debris entry.
7. 7

   Prepare for valve seal removal
   Rotate crankshaft (if not already done) to position the first valve at mid-lift position where valve spring pressure is lowest. Install compressed air adapter into spark plug hole for cylinder being serviced. Apply approximately 90-100 psi compressed air pressure to hold valve against seat. Verify valve is held securely by attempting light upward pressure on valve spring retainer with finger - it should not move. If valve drops, reposition piston closer to TDC for that cylinder. Work on one valve at a time, maintaining air pressure throughout seal removal and installation.
8. 8

   Remove valve springs and old seals
   With air pressure maintaining valve position, position OHC valve spring compressor over valve spring retainer. Compress valve spring just enough to expose valve keepers. Using magnetic pickup tool, carefully remove both valve keepers and place in labeled container. Slowly release spring compressor tension and remove spring retainer and valve spring. Note spring installed height and any shims present. Remove old valve stem seal by gently twisting and pulling upward off valve guide. Inspect valve stem for scoring or wear. Repeat process for all intake valves on one bank, then all exhaust valves, maintaining air pressure on each valve during its service.
9. 9

   Install new valve stem seals
   Clean valve guide tops thoroughly with solvent and compressed air. Lightly oil new valve seal inner diameter with clean engine oil. Using plastic installation sleeve or tapered driver, carefully slide new seal over valve stem and onto valve guide. Tap seal gently and evenly using seal driver or deep socket until seal seats fully on valve guide boss - you will feel a positive stop. Do not over-drive seal as this will damage sealing lip. Verify seal is seated squarely and fully. Note that intake and exhaust seals may be different colors or sizes - install correct type per valve. Install new seal on each valve immediately after removing old seal to prevent debris entry into guide.
10. 10

    Reinstall valve springs and keepers
    With new seal installed and air pressure still maintaining valve position, place valve spring over valve stem (with closer-wound coils toward cylinder head if spring is progressive). Install spring retainer over spring. Using valve spring compressor, compress spring enough to expose keeper groove on valve stem. Apply small amount of assembly grease to keeper groove to hold keepers in position. Carefully install both keepers into groove using magnetic tool or fingers. Slowly release spring compressor while ensuring keepers remain seated in groove. Tap valve stem tip lightly with plastic mallet to fully seat keepers. Verify keepers are properly engaged by attempting to lift spring retainer - it should not move. Remove air pressure and repeat process for remaining valves on that bank.
11. 11

    Clean and inspect mating surfaces
    Thoroughly clean cylinder head deck surfaces, valve cover mating surfaces, and camshaft bearing journals using plastic scraper and degreaser. Remove all old gasket material and sealant residue. Wipe surfaces clean with lint-free rags. Inspect camshaft bearing journals in cylinder head for scoring or discoloration - any damage requires cylinder head service. Clean camshaft bearing surfaces on camshafts with clean solvent. Apply light coat of assembly lube or clean engine oil to all camshaft journals and bearing surfaces in cylinder heads.
12. 12

    Reinstall camshafts
    Carefully lower camshafts back into their original positions in cylinder heads, aligning timing marks as documented in step 4. Ensure camshafts are fully seated in their bearing saddles. Verify valve clearances appear normal by visual inspection - no valves should be held open. No camshaft cap sealant is required — this engine has no overhead camshaft caps. Reinstall pushrods and rocker arms per specification. Install camshaft caps in their exact original positions using orientation marks made during removal. Hand-start all camshaft cap bolts before tightening any.
13. 13

    Torque camshaft caps
    This engine has no camshaft caps; no camshaft cap torque procedure applies. Torque rocker arm fasteners to the documented factory specification for the 8.0L V10. This gradual tightening prevents cap distortion and ensures even valve spring load distribution. After torquing, rotate camshafts by hand to verify smooth rotation with no binding. If binding occurs, loosen caps and investigate for misalignment or debris.
14. 14

    Reinstall rocker arm assemblies
    Verify all rocker arm shaft oil feed holes are oriented correctly (typically downward toward camshaft). Position rocker arm shaft assemblies onto cylinder heads, ensuring rocker arms engage properly with valve stem tips and camshaft lobes. Verify no valves are at maximum lift during rocker installation - rotate camshafts if necessary to position all lobes pointing away from rockers. Install pushrods and individual rocker arms, then torque the rocker arm fasteners to the factory specification for the 8.0L V10. Rotate the engine by hand to verify smooth operation with no interference.
15. 15

    Install valve covers and ignition system
    Install new spark plug tube seals into valve cover seal bores, ensuring they seat fully. Position new valve cover gaskets onto valve covers or cylinder heads per gasket design. Carefully lower valve covers onto cylinder heads, ensuring gaskets remain properly positioned. Install valve cover bolts and tighten in sequence from center outward to 10 Nm (7 lb-ft). Do not overtighten as this will distort covers and cause oil leaks. Install spark plugs into the aluminum heads (anti-seize is optional and, if used, reduce torque accordingly). Torque to the factory specification for the 8.0L V10 aluminum head — verify against service manual. Reinstall ignition coil packs and connect all electrical connectors. Reconnect any harness clips to valve covers.
16. 16

    Reinstall intake plenum and complete assembly
    Install new throttle body gasket and mount throttle body to plenum or intake manifold. Position intake plenum with new gasket onto engine, ensuring all vacuum ports align. Install plenum mounting bolts and tighten in crisscross pattern to even torque. Reconnect all vacuum lines to proper ports using reference marks made during disassembly. Connect throttle cable and cruise control cable to throttle body linkage with proper freeplay. Connect IAC motor and TPS sensor electrical connectors. Reinstall air intake ducting to throttle body. Reconnect negative battery cable.
17. 17

    Refill fluids and initial startup
    If coolant was drained, refill cooling system with 50/50 mixture of ethylene glycol coolant to proper level. Verify engine oil level is correct - top off if necessary to bring to full mark on dipstick (verify total oil capacity against factory specification for the 8.0L V10). Before starting engine, turn ignition key to ON position (without cranking) to pressurize fuel system and check for leaks. Crank engine for 5-10 seconds without starting to build oil pressure. Start engine and verify oil pressure light extinguishes immediately. Listen for unusual valve train noise which should diminish within 30 seconds as new seals seat and oil circulates. Monitor for oil leaks around valve covers.

Reassembly

1. Reassembly is integrated into the main procedure steps, following exact reverse order of disassembly with critical torque specifications applied.
2. Ensure all electrical connectors are fully seated with locking tabs engaged.
3. Double-check that all vacuum lines are reconnected to correct ports to prevent rough idle or poor running.
4. Verify throttle operates smoothly through full range before completing job.

Verification

• Start engine and allow to idle for 5 minutes, monitoring for oil leaks around valve covers and spark plug tubes.
• Verify no excessive valve train noise - light ticking is normal, heavy clattering indicates problem.
• Check for oil in spark plug wells after initial run - oil present indicates improperly seated tube seals.
• Road test vehicle under varying loads and RPM ranges, monitoring for excessive exhaust smoke (blue smoke indicates oil consumption).
• After 50-100 miles of operation, recheck valve cover bolt torque as gaskets may settle.
• Monitor oil consumption over next 500 miles - properly installed seals should eliminate or dramatically reduce oil consumption that prompted repair.
• Check for diagnostic trouble codes related to camshaft position sensors or timing - none should be present.

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