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1986 FORD Sierra RS Cosworth

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1986 FORD Sierra RS Cosworth


The badge ‘Cosworth’ has always been synonymous with performance, and when Ford chose to apply the legendary badging to its line of performance Sierras in the 1980s, they were a predictable success, bringing supercar-beating performance to the masses, with a mind-boggling level of customisation and tuning at the hands of any owner.

Not only was there plentiful tuning opportunities, but also extensive knowledge thanks to an impressive enthusiast base - the chief of which was the renowned RS owners club - and, unfortunately for the owners, a somewhat ill-deserved reputation for fast Ford owners being somewhat flippant when it came to following the letter of the law, though this has largely died out in this modern world of social media, ANPR and automatic speed cameras.

Beginning with an otherwise-unassuming family three-door hatchback, Ford built the Sierra RS with the outright goal of producing a Group A motorsport winner, with Stuart Turner at the head of the table.

By replacing the mundane performance offered by the standard Sierra’s engine with the incredibly tuneable turbocharged YBB block and mating it to a custom-built Borg-Warner manual transmission, Ford were on to a winner.

Underneath, the suspension and chassis were largely influenced by Andy Rouse and Jack Roush and their successful motorsport campaigns in IMSA and BSCC respectively, though numerous production parts from the XR4Ti also found their way underneath the Sierra Cosworths’ bodywork.

Demanding ‘carte blanche’ in order to keep the car stable at high speed when designing the RS Cosworth’s bodywork, designed Lothar Pinske based the body on the XR4i, but incorporated some subtle design changes, and - of course - added the absolutely, not-at-all subtle trademark ‘whale tail’ rear wing, which was necessary for high-speed stability and ground contact.

In the end, a total of 5,545 Sierra RS Cosworths were built, with 500 of these being sent to Tickford for conversion into the even-rarer RS500 models for homologation purposes.

To this day, the iconic ‘Cosseh’ enjoys something of legendary status among both the Ford fraternity and the car enthusiast scene as a whole, whilst extensive tuning and somewhat inexperienced drivers mean that finding a good, non-accident-damaged car is becoming harder and harder.

The Vehicle

Finished in the iconic shade of Moonstone, this 1986-registered Sierra RS was originally delivered to Ireland, with the last-but-one owner (the fourth registered keeper) having custodianship of the car for an impressive 26 years, before passing it on to the fourth owner, who had it for a total of five, and then our vendor, the sixth registered keeper, in April 2021.

According to the vendor, the fourth owner - Angus - kept the car in excellent condition and “looked after it like a baby” with the subsequent owner also having cherished this wonderfully original example of Ford’s everyman performance icon.

Whilst in the care of our vendor, the car has been used sparingly as a weekend toy, and kept in original condition throughout. Serviced immediately following the purchase of the vehicle, the vendor states the car has never required welding and has only needed minor attention to various consumable components, which he has carried out himself.

On the Outside

Moonstone is arguably the best shade for these ‘Cossehs’ and this example is no exception to that rule, and presents in fantastic condition throughout.

On the whole, the bodywork is in excellent condition and looks wonderful, with no impact damage that we can see, nor any noticeable dents, dings or creases. All of the trim is present and correct, and the alignment of panels - on the whole - seems very good indeed.

With regards to the paintwork, this is also in very good shape overall, though there are some notable marks and areas of wear visible on the front bumper and lower ‘lip’ in particular, along with some other marks to the centre and nearside corner of the rear bumper. There is also a tiny bubble of rust noted on the bottom rear corner of the driver’s door, along with a patch of mis-matched paintwork on the offside rear corner of the roof.

Looking closer, there is some signs of ageing and light degradation to the various seals around the vehicle, particularly on the sunroof, though there are no reported water ingress issues at this time, so this should be easy enough to address.

All four wheels are in good order, though they would benefit from refurbishment and re-cutting to bring them in line with the rest of the car, and return them to their former glory.

On the Inside

Untouched by the usual grubby hands of home mechanics and tuners that became synonymous with the RS Cosworth, the iconic Recaro seats and typically understated interior remains in original condition throughout, which is an absolute joy to see.

Naturally, there are some signs of wear, which you’d expect to find on a car of this age and mileage, though this is largely confined to the cracked dashboard (typical of these cars) and some sagging to the headliner.

Speaking of the dashboard, there are also some tell-tale holes on the nearside of the centre console where a carphone system was once mounted, whilst the vendor and photographer both report an intermittent issue with the warning lights on the dashboard illuminating without cause.

There is also some light patina to the high-traffic areas such as the steering wheel, shifter and inner door sills, and some wear to the driver’s seat bolsters, though this is commensurate for the car’s condition and there are no rips or tears that we can see.

Up above, the sunroof is in full working condition with no water ingress issues, though there are some signs of surface ‘bloom’ and corrosion within the sunroof aperture, as seen in the gallery below.

Other than the aforementioned warning lights on the centre dashboard, there are no reported faults with any of the switches or systems within the car.


Under the bonnet, the iconic red-topped YB engine looks to be in good order, and has recently been extensively serviced (more on that in a moment) and is in reportedly full working condition, with no issues other than the aforementioned strange warning lights, though these do not appear to be cause for concern and are assumed to be an electrical issue.

The bay itself would benefit from a significant tidy up and refurbishment, with plenty of surface corrosion to various components, though - as far as we and the vendor can tell - this is purely an aesthetic problem.

Looking underneath the car, the chassis is in good shape, and the suspension components wear only the usual ‘bloom’ of surface corrosion. The exhaust system, by contrast, is in slightly worse shape, with the backbox certainly looking like it’s in need of replacement in the next few years, though it’s apparent originality is certainly appreciated.

The most recent MoT exam - dated 10 November 2021 - shows a clean first-time pass with no advisory items.

History Highlights

Included with the car is an impressive array of invoices, the usual collection of Ford owners manuals, old Irish MoT certificates, the latest British MoT certificate, and some other miscellaneous paperwork.

Allegedly, the fourth owner retains the service record, but this has long been misplaced and a hand-written service interval sheet is included with the vehicle.

In the vendor’s care the car has had the following work carried out since April 2021:

- New Koni front shock absorbers

- New fan temperature switch

- Vodaphone-connected tracker and Class 1 alarm system (£585)

- New central bearing and rubbers

- New exhaust rubbers

- MSD tune and setup

- Rear brake pads and discs

Alongside the above, the vendor also carried out an extensive service in April 2021 at 69,757 miles, consisting of the following items:

- Oil and filter change, using Titan Race Pro-R 10w40 oil

- Gearbox oil change

- Differential oil top-up

- Timing belt and tensioner pulley

- New spark plugs

Finally, the V5 is present showing five former keepers, and a clean HPI report is also included.

What We Think

With its iconic whale tail spoiler, boxed-off three-door body shell and legendary tuner status, the Ford Sierra RS Cosworth really is one of the all-time greats of the performance car world, bringing impressive speed, handling and potential to the masses.

This particular example is in incredibly original condition throughout, having been kept unmolested by its successive owners, something that is becoming harder to come by in the world of classic Fast Fords.

Benefitting from an extensive bout of recent servicing and presented in very good condition throughout, with only a few minor nagging issues to attend to, this is an excellent example of the 80’s icon and one that is ready to use and enjoy, or the ideal basis for a light restoration back to its full glory.

Offered with an estimate of £42,000 to £49,000 this is an opportunity too good to miss for any Ford fans, enthusiasts, drivers or collectors.

Viewing is always encouraged, and this particular car is located with us at The Market HQ near Abingdon; we are open weekdays 9am-5pm, to arrange an appointment please use the Contact Seller button at the top of the listing. Feel free to ask any questions or make observations in the comments section below, or try our ‘Frequently Asked Questions’.

If needed, please remember we have a network of suppliers we work with regularly including: Classic & Sportscar Finance for purchase-financing, Footman James for classic car insurance, Classic Concierge for storing your car plus we have a list of contacts who can help with transport and shipping.  

BORING, but IMPORTANT: Please note that whilst we at The Market always aim to offer the most descriptive and transparent auction listings available, we cannot claim they are perfect analyses of any of the vehicles for sale. We offer far greater opportunity for bidders to view, or arrange inspections for each vehicle thoroughly prior to bidding than traditional auctions, and we never stop encouraging bidders to take advantage of this. We do take a good look at the vehicles delivered to our premises for sale, but this only results in our unbiased personal observations, not those of a qualified inspector or other professional, or the result of a long test drive.

Also, localised paint repairs are common with collectable and classic cars and if they have been professionally carried out then they may be impossible to detect, even if we see the car in person. So, unless we state otherwise, please assume that any vehicle could have had remedial bodywork at some point in its life.

Additionally, please note that most of the videos on our site have been recorded using simple cameras which often result in 'average' sound quality; in particular, engines and exhausts notes can sound a little different to how they are in reality.

Please note that this is sold as seen and that, as is normal for used goods bought at auction, return policy does not apply. See our FAQs for more info, and feel free to inspect any vehicle as much as you wish.

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  • Location: The Market HQ, Abingdon, United Kingdom
  • Seller Type: Private
  • Odometer Reading: 70142
  • Chassis Number: WF0EXXGBBEGU05380
  • Engine: 1993
  • Gearbox: Manual
  • Steering position: RHD
  • Colour: Moonstone
  • Interior: Grey/Red
  • Estimated Price: £42,000 - £49,000

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