1986 BMW M635 CSi

Finished in the classic colour combination of Diamond Black and Pearl Beige, ‘C6 PBT’ is one of just 524 BMW M635CSi cars built for the UK market.

We understand that its bodywork was professionally restored in 2021 – purportedly costing more than £20,000.

The engine was rebuilt in 2018, followed by the gearbox four years later. The seller hasn’t been in a position to use it much, hence this sale, but he did drive it to Cornwall without encountering any problems – and he drove it here. 

Black and chrome is an iconic colour scheme for a reason. Full of menace and yet wonderfully upmarket, few cars of the era have the presence as a well-presented M635CSi.

Of course, being a black car, every single dinks, flaw and dent will be highlighted, which makes assessing it an easy matter.

A quick one too, in this case, because there isn’t much to report other than very good shutlines, great alignment, a lovely stance, and an almost complete absence of damage.

The paintwork has a great shine to it too, and the very good chromework gives a welcome sparkle to what is an appealingly monochromatic finish.

The 17-inch split-rim alloy wheels are in a terrific condition, too. Free of scuffs, scrapes, and other kerbing damage and only lightly tarnished, they’re also fitted with a matching set of 235/45R17 Michelin Primacy tyres. Fitted in 2017, all have little more than legal tread left, and given they are also getting on a bit now, you should probably budget for new rubber. 

Nonetheless, we will never get tired of telling you that experience shows that matching high-quality tyres are an infallible sign of a caring and mechanically sympathetic owner who is prepared to spend the appropriate amount in maintaining their car properly. 

The sunroof fits well too, although there is a small rust bubble on the roof near its perimeter.

Other tidying up includes straightening the rear numberplate, fixing the dent on the front below BMW badge and the one on the offside front wheelarch, and sorting out the scuff on the offside corner of the rear bumper.

There are also cracks in the nearside rear lamp cluster and nearside front indicator lens, a mark on the top of the nearside rear wing, light scuffs to the front valance and offside rubbing strip, a chip on the offside door mirror, rust on the trailing edge of the driver’s door, a blemish on the bonnet, and some very light marks on the offside A-pillar trim.

It would be fair to say that the interior isn’t up to the same standard as the rest of the car – but then if it were, you’d be looking at paying an awful lot more.

Let’s start with the front seats, which are a little soft and stained. But peer more closely and you’ll see that the Pearl Beige leather coverings are merely getting on a bit with the odd patch of colour loss. 

If you don’t mind a patina, then a deep clean would make a big difference – and if you do, then they aren’t even close to being bad enough for them to be a priority.

The rear seats are in a better condition, and the ‘M’ steering wheel and matching gearknob are in a good condition, as are the door cards and pedal rubbers.

The rear parcel shelf and the front footwells have all been fitted with humungous speakers, which we all used to do before we knew any better. The console on the transmission tunnel surrounding the handbrake also bears witness to something like a cradle for a mobile phone having been screwed on there, and the aftermarket radio hasn’t been fitted properly either, so maybe now might be the time to get that all sorted in one fell swoop?

The boot floor is a little rusty, so that’s going to need some attention. It also plays host to a full-size and matching spare alloy wheel, two headrests, some chrome trim, a spare instrument cluster, a heater fascia, and a box of miscellaneous spares; please see the photos for details. 

A partial and somewhat rusty tool kit lives under the boot lid.

The air-conditioning doesn’t work, although the seller tells us he thinks it just needs re-gassing. Otherwise, we are told that everything in the cabin works as it should.

As for wear and damage, the plastic trim for the offside door mirror is broken, the top of the dashboard is cracked in a couple of places, the headlining is dirty and starting to come loose, the carpet in the driver’s footwell and the offside rear footwell is worn, and the offside door pull and door capping are both damaged. 

The straight-six engine was rebuilt by Autotech, an independent BMW specialist, in 2016 at a cost of more than £5,700.

The gearbox was refurbished by Gearbox Man in 2022 at a cost of almost £2,000 too – and that builds on another, nigh-on four-figure bill for a new third gear synchromesh in 2020. 

The result is an engine that bursts into life with enthusiasm, albeit with an engine check light on.

It idles and revs very well, and makes a lovely noise from the twin exhaust tailpipes. While the seller hasn’t been able to drive it as much as he would have liked, he singles out the “strong engine” for particular praise, and says his BMW has never caused him a problem on the journeys he has completed, which included a run to Cornwall as well as the trip up to us. 

The engine is reassuring analogue, so if you’ve got a good toolkit and a logical mind you could service and maintain this car yourself, which be fun and cost-effective, and how many areas of our classic car hobby can you say that about?

The underbonnet sound proofing is in good shape too, and one of the factory stickers is still there too, which bodes well for the originality of the panel.

Given how collectible these are, we can see the new owner might like to refresh the underbonnet area, but we reckon a rattle can of paint for things like the airbox followed by a deep clean would make a big difference.

The seller also tells us that any rust in the floorpans was cut out and replaced during his ownership. The repairs have been neatly undersealed, but there are other patches of surface rust visible, most noticeable in and around the wheelarches, so you might like to take care of those before they turn into something more expensive. 

The BMW’s MoT certificate is valid until March 2026 and it, like every single one since 2020, was issued with no advisories. 

The recent Vehicle History Check is clear, and it comes with two keys and fobs, the owner’s handbook, a bunch of expired MoT certificates, and plenty of old invoices, including those for the engine rebuild. All of which are viewable in the documents section of the gallery.

While many of us lusted after the VW Golf GTI when we were teenagers, often this was only because the thought of owning a top-of-the-range BMW M635CSi was so far-fetched as to be unbelievable; we might have dreamed of owning a Ferrari or a Lamborghini if we won the pools (remember them?) but the idea that a car like this would ever live in our garage was ludicrous.

But dream no more; at a time when the sticker price of a Ford Focus can easily start with a four, cars like this are still surprisingly attainable. 

For now, anyway.

How attainable? Well, we think the virtual hammer will fall somewhere between £30,000 and £35,000, a figure that’s considerably lower than it would have been if the interior had been in a better condition.

Which means you would be adding value as you smarten it up – and this is the automotive equivalent of having your cake, eating it, and then going back for another slice. With cream. 

Viewing is strongly encouraged, and this lot is located at Bonhams|Cars Online HQ. Viewings are STRICTLY BY APPOINTMENT and we are open weekdays between 10am - 12pm or 2pm - 4pm. To make a booking, please use the ‘Enquire About This Vehicle’ button on the listing. Feel free to ask any questions, or try our ‘Frequently Asked Questions’.