No more BMW for this bloke
It's been just over a year since Joe paid around 33,000 Euros for a black BMW M6. He did the background check, the car was fully legal, not one of those shady imports. He still has the car – it's stranded in his front yard, with its mechanical guts spilled all over the place. The engine bay is completely empty, with the wiring harness groping for something to attach to, hoses running down both sides, filled with nothing but dust and air. The suspension and the steering are still intact though.
The remains of the engine are still lying exactly where the roadside assistance guys dumped them after bringing the immobilised BMW back home. Mr J is now relaxed about his ordeal – after all, getting upset over it again and again won't make it unhappen. He brings out the salvaged parts. The cylinder bank, the SMG gearbox and some covers are lined up on the balcony upstairs. The complex twine of downpipes is a piece of art – with sad connotations, but nonetheless. All the rest – the radiator, the air conditioning unit, cylinder heads and pulleys – is downstairs, near the gutted body. There are more parts filling up the boot, including the clutch and some of the electronics.
The wheels, once proud and shiny, now stand dulled on deflated tyres. The brake discs are speckled with rust; it's been a while since they were last used. Judging from the holes peppering the engine block, blasted when the con-rod detached from the piston in the right hand front cylinder, it may be quite a while before they will turn again.
Mr J and his friends were driving home on 28th July, 2012, around 1 a.m. They were cruising on a highway, with absolutely no traffic around. Although they were going fast, it was far from full throttle and their speed was steady, with no acceleration whatsoever. They were nearing city limits when the car suddenly began to act up. First the low oil level warning symbol came on, then it went out again. Amber lights are for warning only; red is reserved for emergencies in a BMW. Knowing they were only some five kilometres from home they decided to keep driving. Also, Mr J had just topped up the engine oil a few days before.
You see, he was in the know. He had been driving the car of his dreams for three months. He bought it from a countryside used car dealership who were selling it on behalf of the first owner. Prior to finalising the transaction Mr J had the car inspected and serviced at a local authorised BMW workshop. They filled up the engine with twelve litres of high quality lubricant, replaced all filters as well as the battery and the rear tyres.
Mr J has lived among cars all his life. He drove a go-kart at the age of six, and began racing them but an accident (more precisely, his parents terrified by his accident) cut his career short. His passion remained though. It takes half a day to condition the leather seats of the M6 yet he was happy to do it himself. He loved fiddling with the car. He never took it racing and he knew the importance of a proper warm-up.
Opening the driver's door I notice a worn spot on the left bolster of the driver's seat. Recorded mileage at the time of the incident was 91,331 km; Mr J drove about 4800 of that. And he loved every inch of it; his eyes still get misty as we stand by the heap of metal that used to be his car. He was crazy about the sound of the V10, the 507 PS, the SMG gearbox. He didn't mind the excessive fuel consumption, with the engine gobbling down as much as thirty litres of premium fuel without breaking a sweat. Once you get over 300 PS or so it is very difficult not to fall in love with a car – at least a bit.
The first thing he noticed is that the car used up 1.5 litres of engine oil within 2300 kilometres. He found that a bit excessive, given that he primarily used the car on short commutes but because official documents allow for up to 1,0 litre/1000 km he wasn't really alarmed. Mr J had the habit of keeping two extra bottles of engine oil in his cars, the same type that is used for normal servicing. Whether it was the Peugeot 206 used as a family runabout, the impeccable Honda CR-V or the Mazda RX-8, he never left home without that extra protection. Especially in the Mazda, of course, as the rotary engine is really fussy about care. It consumes significantly more oil than regular engines do which teaches you to be conscious about your vehicle.
So this is why Mr J did not immediate stop when he noticed the amber symbol on the IC. He had also seen it some weeks earlier while parking the car in front of his home. He quickly called the garage where the initial servicing was carried out and their specialist said the alert might be triggered even if the car is parked on a slope. The M6 is taking no chances.
But around 1 a.m. on that summer day, driving up a steep incline it was becoming obvious that this time a simple top-up would not do the trick. Checking his rear view mirrors as he was preparing to leave the motorway Mr J could not believe his eyes. Illuminated by the eerie red of his taillights, there was thick grey smoke bellowing behind the car. What happened next escapes reason unless you have ever walked in these shoes. Mr J stopped on the shoulder to see whether he was only kicking up some dirt from the road, but the cloud of smoke followed him. It was coming from the car.
Mr J vividly remembers what happened next. He was still looking in the mirror when the car started to slow down and smoke poured inside the cabin. The instrument cluster went red with a plethora of emergency warnings and suddenly there was a cacophony of the most horrid sounds imaginable to a car lover. He remember driving blind for the last few metres as visibility went down to zero. The interior, once home to the fine scent of supple leather, was filled with the stench of burned oil. Smoke started pouring out of the engine bay. The engine started rattling, then shut down, alongside the gearbox.
I was afraid the car would burst into flames so we leapt out of the car and dashed to a safe distance, he recalls the dreadful moment. As the smoke abated they could make out the road and the endless oil spill originating from the BMW. Mr J had the car hauled back home and then organised for a trailer next morning taking the car to his preferred BMW dealership where the initial servicing was done.
The full disassembly of the engine, completed in the presence of expert technical witnesses, revealed that there were several chunks broken off the engine block caused by the con-rod when it went loose. One witness was invited by Mr J while another one was designated by the local notary public. D.Eng. Zoltan Lovasz and Bela Kulcsar were trying to establish whether the engine failure was caused by material fatigue, error in design, or negligence on part of either the owner or the garage.
D.Eng. Lovasz, the expert designated by the notary public was also hoping to find out whether the engine oil spilling over the 600°C catalytic converter posed a fire hazard and also whether the stated mileage was manipulated or not.
As the con-rod in the right hand front cylinder broke off, the piston rotated within the cylinder. The engine stopped running after a few seconds but in this short while there was incredible damage done even though the engine was running at the low speed of 1552 rpm, as recollected from diagnostic data. The broken off components and the scattered shreds of the piston crushed the hoses within the sump and punctured various parts of the engine block. Looking at the remains of the engine you can understand why BMW mechanics declared the engine irreparable and recommended a full replacement instead.
Because the car was six years old at the time of the mishap neither the manufacturer's warranty nor any legally prescribed product warranty applies, meaning Mr J has to bear all expenses. He has received an official quote for the V10 engine, codenamed S85, at €26,300, with another €1670 for the installation. This was certainly out of the question, as the market value of the car was below 33 thousand euros – and that's for a mint vehicle.
Unusual as it may sound, there was full agreement among the two witnesses and the approved BMW garage regarding the diagnosis. The bottom-end bearing of the con-rod was significantly deformed and worn, and rotated freely within its housing. There were three other cylinders where con-rod bearings suffered damages. After ECU recordings were analysed it could be ascertained that there was nothing wrong with the oil level or with the sensors checking the oil level. The inspection also revealed that the engine had not been tuned or otherwise upgraded, and while the engine did overrev at one point, going to 8545 instead of the cut-off limit set at 8250, the experts agreed that this could not have caused the carnage as “this was not excessive”.
None of the reports mentioned the small box marked EX310, clearly visible on both pictures, which was probably inserted into the system without opening up the ECU. A quick web search will tell you that this little gadget serves the purpose of overriding the top speed delimiter and it indeed installs without having to interfere with the ECU. The manufacturer EVC (Entwicklung Vertrieb Communication) claims all it does is clear the speed signal which stops the engine from revving to the delimiter in top gear. BMW also offers the same option for its M vehicles; purchasing one of these factory units requires that the owner takes an advanced driving course.
The report submitted by D.Eng Lovasz makes grave conclusions.
“The clearance between the front crankshaft journal and the con-rod bearings riding on this journal became wider due to wear and a possible slight drop in oil pressure (VANOS control operation). This resulted in insufficient lubrication of the journal which caused the bearing to rotate and burn onto the journal. This in turn broke the con-rod, fracturing the piston boss. [...] The bearings running over the journals display even wear, mediums are worn down to the bronze surface which in itself constituted a possible cause of the subsequent failure, considering how the engine was run at high speeds.“
The fundamental cause of the failure was the wear inflicted on the bearings which could have been a reason of several factors including excessive load, the use of improper lubricants, or the use of bearings and/or journal lubrication not suitable for the relatively high performance and rpm figures, as well as for the frequent utilisation of the full power of the engine.”
The report concludes that, based on data received from the local BMW distributor and from the garage, the first three possible causes can be eliminated.
The invited expert witnesses would not rule out the possibility that the atmospheric V10 engine used in early BMW M5 and M6 models had a design error. For lack of confuting evidence we are pressed to believe these high speed BMW M engines are highly sensitive. This is common knowledge, and also a reason why the official maintenance period for these engines is 10000 km instead of the now customary 20-30K. But apparently even observing the maintenance rules and making sure the engine is properly warmed up is no guarantee of long engine life.
Statement from BMW Hungary
Unfortunately the expert witnesses working on behalf of the Owner have failed to notice the simple fact, obvious from the photograph included in their expert opinion that the car has been subjected to unauthorised modification.
This modification has allowed the engine to rev beyond the limit set by the manufacturer. One of the expert reports claims ‘excessive load' as the most probable cause for the failure. Although the pictures clearly demonstrate that modifications have taken place, said expert has chosen to rule out this specific cause based on data received from the national distributor which, however, were arrived at without knowledge of specific facts the technical witness was aware of after visual inspection.
This means that the prime candidate for the failure, i.e. excessive engine speed, cannot be ruled out. The report submitted by the other witness also states that the motor vehicle “had not been reprogrammed from its factory state for higher load operation.”
We had originally offered a discounted quote on the repairs but this offer was cancelled once we became aware of the subsequent modifications.
BMW Hungary has never experienced such failure within the warranty period of its vehicles. Based on the above the conclusions suggested in the manuscript are not, and never have been, true. We have never stated anything other than that “based on diagnostic readings there seem to be no presence of aftermarket modifications”. However this is not to be interpreted in absolute terms as implied above in the sentence “After ECU recordings were analysed it could be ascertained that [...] the engine had not been tuned or otherwise upgraded,”
Car manufacturers obviously and strongly dislike conclusions being drawn from comments made at internet forums. So when I reveal to you that several international BMW forums maintain specific subforums for discussing engine failures on BMW M5 and M6 vehicles, it is only to be taken as part of our global automotive folklore. Typical symptoms are similar to what Mr J has experienced although a few dozen cases should not make anyone jump into conclusions. Some customers indeed heard the engine knocking before the failure happened.
By now Mr J is pretty much over the trauma. He has located local BMW owners who have experienced similar issues. One of them has lost an engine a few years ago while it was still under warranty. While he received a brand new replacement engine he managed to wreck the car within a short while, meaning he has an available engine with only 30000 km. That would cost Mr J about €9000, plus another thousand or so in installation – not in an authorised workshop, of course. Once that operation is completed his M6 will be as good as when he bought it, meaning he can sell it.
Seven failed V10's, all unique cases
After calamity struck Mr J located an independent BMW technician, Balazs Szekely. He has been running his own business for thirteen years; he used to own a 850i, but has worked with all sorts of cars. Over the last few years Mr Szekely has heard of no less than seven cases when bearings failed on an M56 or M6. He is currently working on one of these; that car failed right after leaving a fuel station and low speeds meant there is actually a slight chance its engine can be restored to working order. Mr Szekely says the removal or installation of an S85 engine requires extreme concentration, making it some sort of a nightmare for technicians. But he will install the lightly used V10 in Mr J's car, once he decides to buy it. The privateer declined to make conclusions over the phone but he was also shocked by the amount of damage done by the runaway components.
Mr. Szekely says it takes mighty little for a high revving, high performance engine to fail but he would not go as far as to say it was all down to design error. I would have liked him to say something positive, a word of consolation for people saving up for or already driving a BMW 6-series. The standard V8 serving in the 645i/650i cannot fail like this, right? Wrong. Bearing failure is also possible there, caused by trite circumstances. There is not enough clearance under the oil pan, meaning even parking the car on the kerb can dent it slightly. But that slight dent is enough to block the oil intake, causing insufficient lubrication. Once that happens it takes nothing more than a single instance of hard driving to damage the bearings. Mind you, BMW have designed and engineered plenty of excellent models, including masterpieces such as this S85 V10. It's just that you need to be careful.
Mr J is finished with the car. We start talking about his Mazda RX-8. He has been driving it for four years and has had it serviced regularly with the nation's best accomplished expert of rotary engines. He knows he must keep the oil level over the maximum mark on the dipstick. He knows the engine must not be revved or shut down during the warm-up phase. And he knows if he keeps those rules the engine can take hard use. Over the 78,000 kilometres it has covered they only needed to work on the powertrain once. An intake flap gut stuck because of some debris, causing the engine to rattle in the 5100-7400 rpm range. It was no easy fix, the entire engine had to be disassembled, and once it was in bits anyway the technician suggested a general overhaul. The whole operation cost 800 Euros and the car has been in perfect running order ever since. The RX-8 has dismal residual values because people are generally afraid of the car. Many feel uncomfortable about having to rev the engine high and hard.
Mr J is not one of those people. He is comfortable with the Mazda but he is completely and irrevocably done with anything BMW. If he ever manages to get rid of the M6 he might buy a Porsche Cayenne Turbo S. Second hand, of course, for cents on the dollar. He is no fool to get parted with his money.
Getting lost in this case I decided to take a look inside BMW's parts registry. This vast database offers several search options beyond the traditional VIN-based one so with a bit of digging you can find out about all the modifications done but not advertised over the years. As of September 2005 the S85 engine of the M5 and M6 engines received a redesigned oil pump with new hoses. Can you take a guess when this particular BMW M6 was made? Bingo – in September 2005. And the specialist says this means the engine most certainly dates from before that time.