Mercedes-Benz ML320 1999
Mercedes Benz started with a fresh sheet of paper when it designed the M-class. There is still nothing else quite like at; for some direct competition we may have to wait to see how the A HREF="../../BMW/BMW.html" --> BMW X5 turns out. In the meantime, the M-class is just about on its own as first and foremost a luxury car with serious four wheel drive ability. It is clearly aimed at buyers of the Range Rover but the current model of the latter is a contradiction - primarily an offroader (if rarely used in that way) and then a luxury car. By luck or good tactics, the ML320 at $67,400 (standard) to $73,400 (luxury) falls between the top $60+K Discovery and the Range Rover ($80+K...$100+K) in price, with the $98,500 ML430 squarely in the latter's price bracket ($au 9/1999).
The ML320 (right) is the 3.2 litre V6 version of the M-class. Its upmarket brother, the ML430, has a 4.3 litre V8 and an ML230 with a 2.3 litre 4-cylinder engine is not available in Australia. The cars are made by (now) Daimler Chrysler in Tuscaloosa, Alabama, USA, and production started in Graz, Austria, in mid 1999.
Driver and passengers sit quite high up in comfortable seats
with generally good views of the road ahead.
The "organic" styling means that the bonnet is rounded
and falls away, putting the front extremities just out of sight,
even with the seats on a high setting (6' driver).
The windscreen is steeply raked and the front pillars
are thick, making for a possible (bike) blind spot.
The suspension is independent with double wishbones at each wheel.
Front springing is by torsion-bars and rear by coil springs.
The suspension is mounted on sub-frames which are attached to a full chassis.
The suspension is oriented towards good handling and, as such,
is on the firm side - for a luxury car.
This car is taking the `S' (sport or at least grand-touring) in SUV seriously.
Fully independent suspension gives the lowest unsprung weight
which basically makes
The 3.2 litre engine spends most of its time between 2000rpm and 3000rpm if driven in a relaxed manner, which does not mean dawdling. 110km/h corresponds to a gentle 2400rpm (indicated), 60km/h to just 1700rpm. Planting the right foot will have the engine up to 4000rpm or more and show quite another side of its character, hurrying the two tons of motor car up to the legal limit, and well beyond if you were to let it, quick smart. Overtaking is not a problem. There is something of a snarl from the exhaust at higher revs, and one wonders whether this note has been deliberately left in by the engineers. Some tyre noise can be heard on noisy surfaces.
The engine and the 5-speed automatic gearbox cooperate well together delivering silky smooth gear-changes. The throttle however is definitely unusual: It takes a large movement to make the engine pick up from idle. This is not an aspect of the engine as such, rather it is something to do with the electronic "drive by wire" throttle set up, and it takes a day or three to get used to it. Perhaps it is a move by the designers to improve fuel consumption by stealth?
The steering is light and has a good feel. It is not over geared however and, with only modest self-centering, more wheel turning than expected is needed to negotiate small suburban roundabouts.
The brakes are also light but have a good progressive feel, giving
opportunity for the ABS, BAS and ESP (!) to sense the driver's intentions.
They inspire great confidence in the wet or dry.
BAS, or `brake assist system', increases braking effort
after rapid (
The parking brake is one of those foot-operated devices
common in American automatics and I will confess to being
antipathetic to them even in 4x2s.
The brake is engaged by a pedal that is
on the left hand side of the driver's foot-well and quite high up.
The release is a hand lever on the lower edge of the dashboard
to the right of the steering wheel, and it releases the parking brake
ratchet in one go, nothing progressive about it, bang.
It is essentially impossible to gradually release the thing which
could be awkward in some four wheel drive situations on steep slopes;
the best that you could do is perhaps to have your left foot on the foot-brake
and your right foot on the accelerator before letting the parking brake off.
Now I don't "get" the cup-holder thing, but
the ML320 is liberally supplied with them and they might well come in useful.
However, the driver's is immediately above the parking brake release
and the natural tendency is to rest your thumb on it in preparation
to releasing the brake
The M-class rated very well in recent US crash tests. Driver and front passenger get front and side airbags. The front seat belts have belt tensioners and force limiters. The outer rear passengers obviously have lap-sash belts, but the centre passenger only has a lap-belt, where the recent trend is to safer lap-sash belts in all positions. The passive safety features are backed up by active features - full-time 4WD, ABS and ESP. (And a sincere vote of thanks: We are spared irritating chimes that remind occupants to put their seat belts on.)
If the ML320's suspension is primarily designed and tuned for on-road conditions, handling road bumps (even in rough roads) with great stability, then it does not have quite the long-travel, low spring-rate suppleness that is possible with live axles. Them's the swings and roundabouts. A really big pot-hole will send back a bigger shock and/or have the suspension reach its bump stops sooner in an M-class than in a you-know-what.
The raw ground clearance figure (210mm) is typical for its class,
but does not tell the whole story.
As in most independent suspension systems,
the lower wishbones are more or less
horizontal and in-line with a subframe lower cross-member.
This means that minimum ground clearance is not just
an isolated low point at the bottom of a diff' housing
but extends across the full width of the car,
and the M-class has this arrangement at both ends.
So it is more likely to get "hung up" on
Tyres are 255/65R16 on alloy wheels giving an overall diameter of 29", a couple of inches short of the traditional 7.50x16's 31" diameter - just think of all those ruts made by Landcruisers. There is plenty of room under the mudguards, in fact a lot of room, so if you wanted to go hard four wheel driving a second set of aggressive tyres might be feasible (and legal if they had the necessary speed rating). The standard spare tyre is a space-saving T155/90D18 which is small enough to tuck up under the rear of the car without hurting ground clearance. It is enough insurance for the highway, a trip to the ski resort, or a day trip near home, but a full-size spare would be needed for a major outback expedition, and where to put it? A carrier on the upwards opening tailgate is impossible. The '98 Motor Show car sported a rear-mounted spare wheel carrier but it seemed to be rather flexible for outback roads. A new spare wheel and carrier are available, in a full rear suspension upgrade, for $2,578 (ML320) or $2,870 (ML430). The alternative locations for a spare are `inside' or on the roof rails (100kg limit). Roof bars have a list price plus tax of $463.
There is a strong looking, steel cross-member across the front
of the chassis, just behind the plastic bumper,
and it has a reasonably sturdy towing point welded to it.
If the car does get stuck hard, the owner's manual prefers
recovering it backwards using the rear tow-bar (if fitted)
as a strong point.
Fully independent suspension does not deliver quite the same axle articulation as a live-axle and can leave a wheel hanging in mid-air if ruts are taken at an angle (right). Given the car's full-time four wheel drive system with a centre differential but nary a diff' lock, this would leave the car without any drive if it were not for the traction control system. This uses the ABS braking system's components to automatically apply the brake on any spinning wheel, thus directing torque to those wheels that still have grip. The only signs to the driver are a warning light on the instrument console and perhaps some noise from the brakes.
Low-ratio gears in the transfer case can be engaged at the press of a button when the automatic transmission is in neutral. This is definitely the simplest of all four wheel drive systems to operate. The main benefits of low-ratio are to increase engine breaking on steep descents and to reduce the load on the transmission on steep, rough climbs. Automatic transmission makes most ascents easy in high or low-ratio. As mentioned there are no locks on any of the three differentials; traction control automatically applies the brakes on any spinning wheels to maintain drive while at least one wheel has grip. If you are going up to the snow, note that if fitted "snow chains must be used on all four wheels" (my italics).
The engine air-intake is tucked away in the front right-hand side wing just above knee height, so deep wading should not be undertaken.
The above points do not indicate that the M-class
is an offroad wimp. It has excellent traction, good clearance
and is very easy to drive, but it does not have that last
bit of hard off-road ability that (say) a live-axle Range Rover has
even if the latter is rarely called upon to use it;
that is clearly a key Mercedes Benz design decision
and indications are that BMW with the X5 and quite possibly
with the next Range Rover will move in that direction too.
The ML320 could also be said to complement the Jeep
The main instruments are a speedometer and a rev' counter. A trip computer is mounted centrally, overhead. There are three stalks on the steering column: (i) wipers to the right, (ii) lights and indicators, and (iii) cruise control to the left.
Surprisingly a radio / tape player is standard - a CD player is a $1K option on the ML320!
Interior lighting is well done: automatic illumination with fades on entry and exit of course, push the lamp cover to turn an interior light on if necessary, a light in the glove box (we think it goes out when the box is shut), flip-down mirrors with lights in both sun visors, and so on. The trim on this particular car was a light, rather orange, tan colour which might not appeal to all tastes.
There are many small but thoughtful design features in the ML320. e.g. The "blade" of ignition-key folds into the body of the transmitter for the central-locking. Non-slip rubber mats in the shelves of the central console keep sun-glasses etc. in place. The clips for the security "blind" over the rear load area are moulded into the trim. There is no release lever for the fuel filler, because the cover is (un)locked when the doors are (un)locked (you do however feel foolish after having searched for the release).
On a day trip, two hours out from the city, a day on bush tracks, and two hours back, consumption of about 14.2 litres per 100km (~20mpg imperial) was measured. Around town a figure of about 16.5L/100km (~17.3mpg) was returned. This is consistent with the maker's claims of 18.2L/100km urban, 11.2L/100km country, and 13.8L/100km overall "as per 93/116/EEC".
ML320 best feature: effortless driving.
Worst feature: that parking brake.
Could you live with the car?
Mercedes Benz ML320 1999Manufacturer's figures:
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