The Sierra Cosworth RS500 a much uprated version of the production Sierra 3 door Cosworth. Only 500 of these special vehicles were produced, all modified by Tickford. This Cosworth was announced in July 1987 and was homolgomated in August 1987.

The RS500 was only available in RHD (Right Hand Drive), althought some of these may have found owners on mainland Europe.

The main difference to the Sierra 3 door Cosworth was the uprated Cosworth competition engine. It's new features were:

• The engine had a thick walled cylinder block to cope with the rigours of the track.
• A larger turbocharger and intercooler was fitted.
• To the fuel system a second set of injectors was added and uprated fuel pump. Fuel injection used Weber/Marelli equipment.
• The oil and cooling system were both also uprated.

All Cosworth engines are fitted with hardened valve seat inserts and can therefore run continuously on unleaded fuel. With ordinary unleaded petrol it is necessary to retard the ignition by 4 Degrees. A power loss of approximately 10 bhp will be experienced after the ignition is retarded. Retarding the ignition may not be necessary if the engine is always run on Super unleaded fuel.

A genuine RS500 Cosworth engine should be labelled in the range YBD0015 to YBD0537 .

Genuine RS500 shells were labelled GBBE GG 38600 to GBBE GG 39099 . These chassis labels are found under a small flap next to the drivers seat and also mounted in the engine bay. Both should display the same numbers.

The RS500 had only minor external cosmetic differences to its parent the Sierra 3 door Cosworth:

• The rear tail gate also had a lower spolier in additional to the upper whale tail.
• This Cosworth had discrete RS500 badges on the rear tail gate and front wings.
• Re-designed front bumper and spoiler to aid cooling and air flow.
• The bonnet louvre air vents were also of a slightly different design.

Available colours where, (with production figures in brackets):

• Black (392)
• White (52 plus 4 Ford prototypes)
• Moonstone Blue (52)

UK price guide (Sterling)

Note the RS500 is a rare vehicle and hence the prices reflect this. Potential buyers would be lucky to find one available for less than 15000 Sterling! This Cosworth remains today one of the most sought after modern RS marques.

Condition       Excellent   Good    Average

Sterling         15000      Not  Applicable

Note: The FORD Sierra Cosworth RS500 3-door was produced on D and E-registration plates in the UK.

For further details see Vehicle Registration Plate Guide.

NOTE: For turbo longevity it is recommended that the Sierra Cosworth RS500 along with all other turbocharged RS models run with fully synthetic oil. These types of oil give the necessary engine protection for the high temperatures attained in turbocharged vehicles. The following viscosity synthetic oils are recommended: 5w50, 10w40, 15w50, 10w60.