Market Segment:
Performance Sedan/Hatchback, homologation special
Key Competitors Era:
BMW M3 (E30/E36), Mercedes-Benz 190E 2.3-16/2.5-16, Audi Quattro, Mitsubishi Lancer Evolution, Subaru Impreza WRX
Defining Features:
Cosworth YB engine, permanent all-wheel-drive, advanced chassis tuning, iconic styling, motorsport heritage
Target User:
Enthusiast owners, independent workshops, restoration specialists
Engine:
Cosworth YB 2.0L Turbocharged DOHC
Transmission:
Ford MT75 5-speed manual, BorgWarner T-5 (earlier variants covered implicitly)
Drivetrain:
All-Wheel Drive (4x4) system, viscous coupling unit, rear differential
Suspension:
Independent front (McPherson struts), Independent rear (multi-link), anti-roll bars, bushings
Brakes:
Front: Ventilated discs with 4-piston calipers (AP Racing on RS500), Rear: Solid discs with 2-piston calipers, ABS
Steering:
Power assisted rack and pinion
Fuel System:
Bosch L-Jetronic (early), Bosch Motronic M1.8, multi-point fuel injection, turbocharger, intercooler
Electrical:
Complete wiring diagrams, ECU, sensors, ignition system, charging system, lighting, accessories
Bodywork:
Chassis, body panels, aerodynamic aids (spoilers, splitters), interior trim, glass
HVAC:
Heating, ventilation, and air conditioning (if equipped)
Maintenance Routine:
Oil changes, filter replacements, spark plug replacement, coolant flushes, brake fluid changes
Troubleshooting Diagnostics:
Step-by-step diagnostic procedures for all major systems, fault code interpretation
Engine Repair:
Engine disassembly, assembly, head gasket replacement, piston ring replacement, valve guide replacement
Transmission Repair:
Clutch replacement, gear synchro replacement, bearing replacement, seal replacement
Brake Service:
Brake pad/disc replacement, caliper overhaul, brake line replacement, ABS system bleeding
Suspension Component Replacement:
Strut replacement, shock absorber replacement, bushing replacement, ball joint replacement
Electrical Component Diagnosis And Replacement:
Alternator, starter motor, ECU, sensor testing and replacement
Turbocharger Service:
Inspection, seal replacement, oil line maintenance
Body Panel Alignment And Replacement:
Door, bonnet, boot, fender adjustment and replacement
Interior Trim Removal And Installation:
Dashboard, door cards, seat removal
Depth:
Detailed overhaul procedures, factory specifications, torque values, diagnostic charts
Engine Type:
Cosworth YB 2.0L Turbocharged Inline-4
Bore X Stroke:
90.8 mm x 77 mm
Compression Ratio:
8.0:1 (standard RS), 7.5:1 (RS500)
Valvetrain:
DOHC, 16 valves, belt-driven camshafts
Turbocharger:
Garrett T4 (RS), Garrett T3/T04B (RS500) with intercooler
Horsepower:
220-225 PS (164-168 kW) for RS, 255 PS (189 kW) for RS500
Torque:
275-280 Nm (203-207 lb-ft) for RS, 360 Nm (266 lb-ft) for RS500
Fuel Delivery:
Bosch L-Jetronic / Motronic, Electronic Fuel Injection (EFI)
Fuel Type:
Unleaded Premium (98 RON minimum recommended)
Fuel Pump Type:
Bosch high-pressure electric
Recommended Oil Viscosity:
10W-40 or 15W-50 (synthetic recommended)
Oil Capacity:
4.5 Liters (with filter)
Transmission Type:
Ford MT75 5-speed manual transaxle
Optional Transmission:
None for RS variants, but earlier Sierras offered automatics
Drivetrain Layout:
Permanent All-Wheel Drive (RWD bias with front axle engagement)
Gear Ratios Mt75:
Typically: 1st: 3.15, 2nd: 1.94, 3rd: 1.36, 4th: 1.00, 5th: 0.77
Fluid Type:
API GL-4 or GL-5, SAE 75W-90 (Synthetic recommended)
Fluid Capacity:
2.0 Liters (MT75)
Oil Change Interval:
Every 7,500 miles or 12 months, whichever comes first.
Air Filter Replacement:
Every 15,000 miles or 24 months.
Spark Plug Replacement:
Every 30,000 miles (check type: copper vs. platinum).
Coolant Change Interval:
Every 30,000 miles or 24 months.
Timing Belt Replacement:
Every 60,000 miles or 5 years (critical for the Cosworth YB).
Coolant Type:
Ford Super Plus Premium Coolant (or equivalent ethylene glycol-based antifreeze with corrosion inhibitors)
Brake Fluid Type:
DOT 3 or DOT 4 (ensure clean system)
Engine Problems:
Head gasket failure (especially if overheated), turbocharger seal leaks, oil surge issues.
Electrical Problems:
Wiring loom degradation, sensor failures (e.g., Crankshaft Position Sensor), ECU issues.
Chassis Corrosion:
Rust around wheel arches, sills, and suspension mounting points is common if not maintained.
Cooling System Reliability:
Original radiators can be prone to leaks; regular flushing and correct coolant mix are vital.
Differential And AWD System:
Viscous coupling unit can seize if fluid is neglected; differential seals can leak.
Ford Motorsport Legacy:
Built on Ford's extensive rallying and touring car racing heritage, especially the Escort RS Cosworth.
Sierra Platform:
Developed from the standard Ford Sierra, but heavily modified for performance by Ford Special Vehicle Engineering (SVE) and Tickford.
Rs Variants Evolution:
Evolved from earlier RS Cosworth models, incorporating chassis refinements and engine updates. The RS500 was a limited-run homologation special for Group A touring car racing.
Manufacturing Location:
Ford's Genk plant, Belgium (primarily for RS variants)
Production Years Rs Variants:
1987-1992 (RS Cosworth), 1987 (RS500)
Rarity Rs500:
Limited to 500 units worldwide, making it highly collectible.
