1992 ROLLS-ROYCE CORNICHE

Typical onset: 70,000-120,000 mi

Symptoms: Car sits low on one or both ends, especially after sitting overnight, Hydraulic pump runs constantly or not at all, Fluid leaks at accumulators or height corrector valves, Compressor overheating

Fix: System uses mineral oil (LHM fluid), not ATF—mixing kills seals. Typical repair involves replacing both rear accumulators ($800 each OEM), front struts with integral accumulators ($1,200 each), pump assembly, and all corroded lines. Plan 12-16 hours labor because access is nightmare-level. Aftermarket coil-spring conversions exist but hurt resale.

Estimated cost: $4,500-8,000

Typical onset: 80,000-130,000 mi

Symptoms: ATF in coolant or coolant in transmission (strawberry milkshake fluid), Transmission slipping or delayed engagement after cooler failure, Visible transmission sag or clunking on acceleration

Fix: The TH400's external cooler corrodes internally, cross-contaminating fluids. Requires cooler replacement, complete fluid flush of both systems, and often transmission rebuild if contamination went unnoticed. Rubber transmission mounts collapse from age regardless of mileage—replace as a set during any major trans work. 8-10 hours for cooler/mount job, add 20+ hours if rebuild needed.

Estimated cost: $1,800-3,200 (cooler/mounts); $6,500-9,500 (if rebuild required)

Typical onset: 60,000-100,000 mi or after extended storage

Symptoms: Hard starting, especially when hot, Stumbling or dying at idle, Loss of power under load, Check engine light (if equipped) for lean condition

Fix: The Bosch K-Jetronic CIS fuel injection uses fine mesh filters that clog with varnish from old fuel. Main filter is accessible (1 hour), but the pre-pump sock filter in tank and injector screens require tank drop (6-8 hours). Cars stored over one winter often need complete fuel system cleaning including injector ultrasonic service. Replace fuel accumulator while tank is down—they leak internally and cause hot-start issues.

Estimated cost: $800-1,200 (filters only); $2,500-3,800 (full system service with tank drop)

Typical onset: 120,000-180,000 mi

Symptoms: Loud rod knock, especially on cold start, Metal shavings in oil filter, Low oil pressure below 20 psi at idle when hot, Excessive blowby or oil consumption over 1 qt per 500 miles

Fix: The 6.75L is essentially bulletproof until it isn't—main and rod bearings suddenly give out, often from years of extended oil change intervals or low-quality oil. Once knocking starts, you're looking at full teardown. Crank grinding is often needed, pistons/rings, main/rod bearings, timing components. Short block replacement is faster but costs more in parts. Budget 40-50 hours for in-chassis rebuild, 30-35 for short block swap. Heads rarely need work unless overheated.

Estimated cost: $12,000-18,000 (full rebuild); $15,000-22,000 (short block replacement)

Symptoms: Ride quality randomly switches between very soft and harsh, ARC warning light illuminated, Suspension pump cycling erratically, One corner behaves differently than others

Fix: The electronic valve block that controls damper stiffness corrodes internally from moisture in the hydraulic fluid. Requires valve block replacement (NLA from Rolls, used units $1,500-2,500) and complete system flush. Some specialists retrofit simpler manual valves. 6-8 hours labor including fluid replacement and bleeding.

Estimated cost: $3,000-5,500

Typical onset: 90,000-150,000 mi

Symptoms: White smoke from exhaust, Coolant loss with no visible leaks, Oil contamination in coolant (or vice versa), Overheating episodes

Fix: Usually caused by failed radiator, water pump, or thermostat being ignored. Aluminum heads on iron block means different expansion rates—overheating warps heads. Both heads must be removed, checked for flatness (often need milling), new gaskets, ARP studs recommended. Valve job while heads are off adds cost but smart preventive. 24-30 hours labor, more if heads need machine work.

Estimated cost: $6,500-10,000