BMW Problems

Some of these older luxury cars are tremendous bargains. Or, at least, they look like it in the classified adverts. There are a couple of reasons they're so cheap second-hand. The first is that people are (often rightly) scared of them going bang in an expensive way and requiring lots of pricey repairs. The second is called the funnel effect and happens when a luxury car like the 7-Series is bought brand-new usually by corporate customers. But, when the car is ready to be traded in a few years later, there simply isn't the volume of private buyers waiting for one to hit the market. So prices plummet. The same thing happens to Mercedes-Benzes, Audis and other luxury brands, too; it's not just a BMW thing.

Meantime, the rules of engagement are the same for any used car. The most important thing is not the distance the car has covered, but how well it's been maintained over the years. You need to see a stamped, up-to-date service handbook with no glaring gaps in the service history. Without that document, you could be buying an abused car that will let you down and empty your wallet.

The other thing to be a bit wary of in a 7-Series BMW of this vintage is the ex-hotel courtesy car. Back in the day, BMW had plenty of 7-Series to shift and a relative lack of takers, so the company offered them to hire-car and limousine taxi operators for about the same (leased) cost as a Holden Caprice. That's how so many of them wound up wearing a groove from the city to the airport.

A good, well maintained ex-hire car should be okay, but bear in mind a lot of them led pretty hard lives. That included a variety of drivers who may or may not have cared very much and long hours idling in gridlock traffic. Check the condition of the backseat to see whether it's been used often (does the wear in the back match that in the front?) and check the area around the rear bumper. This was often damaged as a million suitcases were loaded and unloaded from the boot.

You’d think this would be a fairly simple question to answer, but in reality, it’s far from it. It seems neither BMW nor Porsche offer what we know as fixed or capped price servicing, that is; a known price that the service will cost, paid when you need to have it carried out. This is not uncommon with prestige brands and reflects the changing costs of imported service parts as well as different marketing approaches.

BMW, however, comes closest to this concept with what it calls its Service Inclusive Basic Plan which requires the car’s buyer to pay up front, typically for the first five years, of servicing when the car is purchased. That sounds odd, but it makes sense to buyers leasing their cars as the service costs are then paid for as part of the financing package.

In the case of the BMW X4, this package, which covers consumables such as filters, oil, spark plugs and brake fluid (but not clutches, brake pads and windscreen wipers; that’s another step up to the Service Inclusive Plus Plan) lasts for five years or 80,000km (whichever comes first) and works out to an average of $350 per service or a total of $1750 over the plan’s duration. Fundamentally, it’s like other car-makers’ capped-price servicing but you pay up front for it.

Meanwhile, at Porsche, the servicing costs for a Macan over the same 80,000km/five-year period will depend on what state you live in as labour rates vary from state to state. Since you’re from NSW, I’ll use the data from that state. As such, the Macan will need an annual service at one-year/15,000km costing $695. The next service at two years/30,000km is an intermediate service at $995, followed by another annual service at three years/45,000km ($695 again). The four-year/60,000km service is a major one costing $1750, followed by the five- year/75,000km service at $695 to end with. In total, that’s a grand total of $4830, making the Porsche by far the most expensive car to service for those first five years.

The engine in the car you’re looking at has the codename N42. It has a timing chain rather than a rubber timing belt, so that should not need to be changed for the life of the car. However, life is not always that simple and the N42 has a bit of a reputation for developing wear in the tensioners that keep the timing chain taut. If that happens, you could have a chain loose enough to jump a few teeth on the timing gears and destroy the engine in the process. So a service record and close inspection of the engine is called for before any purchase.

This model BMW was also caught up in the Takata airbag recall debacle. As a result, many BMWs of this era were actually bought back by BMW and scrapped as the cost of fixing the airbag woes was greater than the value of the cars themselves. Make sure any car like this has had the airbags replaced and is not a candidate to be crushed rather than fixed. Quoting the car’s VIN to a BMW dealership should reveal all.

Both the existing Genesis G90 (and its closely related Kia K9 sedan) are flagship models not available in Australia due to the tiny pool of buyers that swim in the upper-luxury segment dominated by the Mercedes-Benz S-Class.

The main stumbling block is probably the prohibitive cost of engineering these left-hand-drive market models for right-hand-drive. At over 5.2 metres long (and counting if you include the limo version), these are way too large for British roads, and the expected sales volumes from the rest of the right-hand-drive countries combined including Australia just doesn't make a viable business case for them.

Plus, big luxury SUVs are where the customers are heading, so a luxury crossover flagship from fledgling Genesis would make much more sense anyway. Sorry, but please don't hold your breath for a G90 in Australia any time soon.

However, the all-electric G80 – Genesis' big 5 Series-priced rival – is said to be heading Downunder inside the next 12 months. The EV limo is the brand’s first fully electric model and will have “more than 500km range” to take on the coming Mercedes-Benz EQS electric luxury flagship sedan.

Run-flat tyres were the car companies’ way of making more luggage space and cutting cost from each car. But they had their problems including the noise you’ve mentioned as well as a lack of ride quality. Although, to be fair, the latter has improved massively in recent years with new generation run-flats hitting the market.

A good tyre specialist should be able to advise you on which run-flats are the current favourites in terms of noise and ride, as well as grip and price. But it’s worth mentioning that tyre manufacturers are constantly trying to outdo each other, so the improvements keep coming. The best tyre today might not be the best one in a few months’ time.

The concept of a larger (wider) tyre on the rear of your car is to do with grip and handling. Messing about with this relationship could lead to a less athletic car and there are physical limits on what tyre can be fitted to what rim.

You could make the switch to a non-run-flat tyre and buy a tyre repair kit to keep in the boot. In fact, many owners of earlier cars with run-flat tyres have done just that. You still stand to pick up a little ride comfort by doing so, but nowhere near as much of an improvement as you would have, say, a decade ago.

The biggest determining factor in how a car copes with tougher terrain is driver behaviour. Drive the car sensibly, sympathetically and to the conditions and you'll be amazed where most cars will happily take you. But get it wrong and drive in a ham-fisted way, and even the roughest, toughest four-wheel-drive will suffer and fail.

The BMW X5 is a soft-roader at best, but should definitely have the suspension to tackle rough roads (as opposed to off-road). The biggest challenge will be the tyres fitted. Many of these vehicles had huge wheels with tyres with very little sidewall. These tyres are easily damaged on rough roads.

Since luggage space is not a critical issue for you, I'd suggest buying a full-sized spare tyre that fits the car, as the SUV's usual space-saver or tyre repair kit can be fairly useless in such conditions. But you also need to be honest about your intentions. By mud and water, do you mean the odd puddle, or 10km of rutted farm track with bog-holes for good measure? If there's any off-road work at all, then you need an off-road four-wheel-drive, not an SUV.

I've used the last versions of both those models for this comparison, which means a 2019 BMW 320d and a 2021 Mercedes-Benz 220d (I'm also assuming you're comparing diesels with diesels).

As such, the BMW holds a slim on-paper advantage with an official combined fuel consumption number of 4.4 litres per 100km, compared with 4.7 litres for the Benz. In the real world, that difference is a very, very small one and means the two vehicles are more or less line-ball for fuel economy.

Real world fuel consumption has a lot more to do with your driving environment and style than it does these laboratory-produced numbers. But the official numbers are valid on the basis that both vehicles were subjected to the same strict test regime, so they do provide a direct comparison, even if you'll almost certainly never match them in real life. Both, however, will surprise you with how frugal they can be.

There are two likely suspects here. The first is a blown head gasket which is allowing the oil and coolant to mix. Sometimes this shows up as oil in the coolant, sometimes as coolant in the oil. Sometimes both.

But before tearing the engine to pieces to change the gasket, it’s worth checking if the car is fitted with either an engine or transmission oil cooler. These often use the engine’s coolant to keep the oil or transmission fluid cool, and a failed one can allow the two fluids to mix, showing up as oil in the radiator or header tank.