1990 Ford Sierra Sapphire RS Cosworth 4x4

The Ford Sierra RS Cosworth (1986-1987) was the 3-door homologation special. Cosworth YB turbo with 204hp, whale-tail spoiler, limited-slip diff. Around 5,500 built. The legend begins. Values from £50k.

Sierra Cosworth: Engine - YB Cosworth turbo. Head gasket critical (especially early RS500s), timing belt every 36k, water pump, turbo (Garrett T3/T4). Strong if maintained. RS500 - even more stressed. Gearbox - T5/MT75 5-speed strong. 4x4 (Sapphire) - viscous coupling, transfer box. Body - Less rust than 70s Fords but check sills, inner wings. Rear spoiler expensive. Authenticity - Check chassis plate, build spec. Values rising - RS500 commanding serious money. Budget £4-8k annually.

RS500 (ultimate), 3-door RS (iconic), Sapphire 4x4 (practical), Unmodified, Matching numbers, Full history