Toyota Prado D4-D

Perfecting Prado

Toyota's 120-series Prado was introduced in 2003 with just one major sore point - the lackluster carry-over 96kW turbo-diesel engine from the Prado 90. Then, in 2006, Toyota released a new D4-D turbo-diesel engine in the Prado, with a heap more power and torque. Suddenly, picking the diesel Prado over the petrol V6 didn't mean you became a second-class citizen in terms of power - even though not an outright top-speed contender, the new diesel at least held the promise on paper of becoming a strong heavy-duty hauler. Now all we needed was to hitch up to find out.

The Prado comes in Standard, GX, GXL, VX and Grande variants, with the Prado turbo-diesel range starting at $45,100 while the top-level Prado Grande is $78,087 (plus on-road costs).

GRANDE GRAND
If you go for the best turbo-diesel Prado, the VX Grande, there is plenty of standard equipment. Front, side and side curtain airbags, ABS brakes with brakeforce distribution and brake assist, traction control, stability control, cruise control, 180-litre fuel tank capacity, tilt/reach adjustment steering wheel, leather interior, power front seats, in-dash CD player with MP3 and Bluetooth functions, satnav, rear-view camera, climate control air-conditioning, trip computer, refrigerated cooler box, sidesteps, eight seats and 17-inch alloy wheels are all standard.

The Grande dashboard uses Optitron backlighting which makes the instruments very easy to read, even in direct sunlight, which was always a problem with earlier generations of this design. Vision from the driver's seat is very good, except to the rear where a rear-mounted spare wheel encroaches on the rear view (although the Grande's rear-view camera does solve this problem).

The interior is well designed and spacious, even if the third-row seats don't fold into the floor like those in the Pathfinder and Discovery 3. At least the third-row seats that fold up against the cargo sidewalls (a very dated method) can be easily removed if not required.

REPOWERED
The Prado gained a more powerful and fuel-efficient turbo diesel engine in 2006, the 1KD-FTV (also given the D-4D name) 3.0lt twin-cam, common rail, turbocharged, intercooled diesel with 31kW more power and 67Nm more torque than before.

The new engine features twin counter-rotating balance shafts, which Toyota claims reduce noise, vibration and harshness (NVH) and a variable-vane turbo with a water-cooled bearing housing.

The Euro 4 emissions compliant engine has a 32-bit engine control computer supervising the electronic engine management, an electronic drive-by-wire throttle, and electronic high-pressure (common rail) fuel injection.

The engine control software cuts off the air-conditioner compressor for high engine-load situations, such as towing up steep hills.

The Prado turbo-diesel interestingly has a fuel cooler to maintain fuel viscosity and precludes the problem some high-pressure diesel vehicles have of boiling fuel if the tank is run low.

The five-speed automatic transmission is linked to a dual-range full-time four-wheel-drive system with a torque-sensing centre differential (which mechanically locks into low-range).

The 3.0-litre D-4D performs well with a predictable amount of turbo lag at low rpm that makes a smooth transition into the mid-range once revs reach about 2000. While a distant, trademark diesel rattle is audible inside the cabin, the Prado is a reasonably quiet 4WD.

The five-speed automatic provides well-matched ratios that are not as imperceptibly smooth in shifts as some competitors' transmissions can, be but are not rough, either - more like an occasional, slightly abrupt shift. The manual mode is especially easy and intuitive to use.

ON THE POCKET
The Prado D-4D has an official 9.3lt/100km fuel consumption average for combined city/highway use. With two tonnes towed behind it, the Prado peaked at 14.0lt/100km on test.

Performance is not cutting edge for the competitive medium 4WD wagon segment, but cannot be described as slow, which its predecessor certainly was. It's a responsive, tractable engine that remains quite economical when driving solo.

The Prado has a reasonably sophisticated suspension system for a 4WD, with coil strut front suspension and a live axle at the rear, suspended in the Grande's case by air springs (coil springs on other models). The Grande also has adjustable dampers, controlled by a console-mounted rotary switch.

Ride quality is very good, which is more noticeable as the roads get rougher.

The Prado is not really a driver's 4WD, but at least it has reasonably responsive and direct steering. The chassis' tendency is to push wide and to do so early into a corner, and to lean with a fair degree of body roll.

The Prado Grande is quiet when driving on rough roads, but with its live rear axle, is susceptible to lateral movement when driving over corrugations or potholes, requiring more steering corrections to maintain a brisk pace on poor road surfaces.

It is fair to say that the Grande's adjustable dampers and adjustable ride height give it better dynamics over other Prados, but it's still not as adroit as some other SUVs. The Prado, like many of its competitors, is built for comfort, not speed - and the bonus is that it performs very well off-road.

STABLE TOW
The Prado is a very stable towing platform that feels as though it will easily handle up to its 2500kg total permitted towing weight and 250kg towball download maximum.

Side mirrors are large and hill-climbing was adequate towing a 2000kg trailer.

Toyota recommends the use of a weight-distributing hitch as necessary and the genuine accessory towbar will accommodate such a hitch when it is set-up properly. Toyota also recommends the use of anti-sway devices where the trailer weight is greater than the vehicle weight, and suggests that the auto transmission should be left in 'D' when towing, noting that with ambient temperatures of more than 30°C, that the engine is susceptible to overheating.

While the 3.0-litre turbo-diesel engine's service intervals are every 10,000km, Toyota does not list extra requirements when towing, but instead suggests to contact your dealer to ascertain what additional servicing may be required according to how much towing is done.

There are few 4WD mid-size wagons that are as accomplished as the Prado. It is very well made, with a convenient and spacious interior, plus the diesel engine blends a decent amount of power with decent fuel economy. While the dynamics are not at the pointy end of its category and interior packaging is not first-class, these are relatively minor complaints for what can only be described as a good all-round package. For further information, visit www.toyota.com.au