The 1991 Silver Spirit pairs Rolls-Royce build quality with aging hydraulic and electronic systems that demand expensive specialist attention. The 6.75L V8 is durable but high-mileage examples face costly engine internals work, while the GM-based 3-speed automatic and hydraulic systems are chronic weak points.
Engine Internal Wear - Pistons, Rings, and Bearings
Common · high severityTypical onset: 80,000-120,000 mi
Symptoms: excessive oil consumption (1qt per 500-800 miles), blue smoke on startup and deceleration, low compression on multiple cylinders, metallic knocking from bottom end, oil pressure drop at idle
Fix: Full engine rebuild required in most cases: remove engine, disassemble, replace pistons, rings, main and rod bearings, machine crank if scored, reseal everything. 60-80 labor hours minimum. Short-block replacement is 40-50 hours but parts availability and cost make full rebuild more common.
Estimated cost: $15,000-25,000
Hydraulic System Failures - Self-Leveling and Ride Height
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: vehicle sits low on one or more corners, ride height pump runs constantly, hydraulic fluid leaks under car (green fluid), rough ride quality, warning lights on dash
Fix: Hydraulic accumulators leak internally (all four spheres typically done together), plus pump seals and reservoir. Hydraulic lines corrode at fittings. System needs complete flush. 12-18 hours for comprehensive hydraulic system overhaul including all accumulators and pump service.
Estimated cost: $3,500-6,500
Transmission Oil Cooler and Shift Solenoid Failures
Common · medium severityTypical onset: 70,000-110,000 mi
Symptoms: harsh or delayed shifts, transmission slipping in 2nd or 3rd gear, no upshift or stuck in gear, transmission overheating, brown fluid in coolant or coolant in transmission
Fix: GM 400 transmission uses external oil cooler that fails and cross-contaminates with coolant. Shift solenoids fail from heat and age. Cooler replacement is 4-6 hours, solenoids require pan drop and valve body work (6-8 hours). Often both done together with full fluid flush and filter.
Estimated cost: $1,800-3,200
Fuel System Deterioration - Injectors and Lines
Occasional · medium severityTypical onset: Any mileage on neglected examples
Symptoms: hard starting when hot, rough idle and misfires, fuel smell in cabin or engine bay, fuel leaks visible on manifold, poor fuel economy
Fix: Bosch K-Jetronic system uses rubber fuel lines that harden and leak, injectors clog from sitting. Complete fuel system service: all rubber lines, filter, injector cleaning or replacement. 8-12 hours for thorough job including intake plenum removal.
Estimated cost: $2,000-4,000
Electrical Gremlins - Central Locking and Window Modules
Common · low severitySymptoms: windows move slowly or stop mid-travel, central locking cycles randomly or fails, door modules click repeatedly, interior lights stay on, battery drain overnight
Fix: Door control modules fail from moisture and age, window regulators bind and overheat motors. Individual module replacement requires door panel removal (2-3 hours per door). Window regulator service adds 1.5 hours per side. Diagnosis is time-consuming due to interconnected systems.
Estimated cost: $800-2,500
Head Gasket Failure from Overheating
Occasional · high severityTypical onset: 90,000-130,000 mi
Symptoms: white smoke from exhaust, coolant loss with no visible leaks, overheating under load, milky oil, rough running and misfire
Fix: Aluminum heads on iron block prone to gasket failure if overheated even once. Both heads must come off, surfaces machined flat, new gaskets and head bolts. While open, do valve seals and guides. 35-45 hours labor. Often leads to discovering bore wear requiring full rebuild.
Estimated cost: $8,000-12,000
Only buy if you have a $10k emergency fund and access to a knowledgeable specialist - these are magnificent when sorted but financial disasters when neglected.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.