Okay guys, let’s take these little 4X4s off the tarmac

Hi Baraza,
Congratulations for the excellent job you’re doing. I have two questions:
1. Please give a critical analysis of the following high-end 4X4s: Range Rover, Land Rover Discovery, Audi Q7, BMW X6, Porshe Cayenne, VW Touareg and Mercedes M-class and G-Class.

Comment on performance on and off road, intelligence, comfort, safety, longevity and fuel consumption, and which of these you woul go for.

2. Please advice us on the precautions we should take to ensure we don’t get conned when importing a car and when buying a locally used one.

Thanks,

Sam.

1. On-Road Performance: The Porsche Cayenne is untouchable, especially as a Turbo or Turbo S. The rest would only attempt at catching up in their high performance variants, and the pecking order is like this, starting from second place (after the Porsche): BMW X6 M, Mercedes-Benz ML63 AMG, Range Rover Vogue Supercharged — if there was a Range Rover Sport in this list, the Sport Supercharged would be No 2 after the Cayenne —, Audi Q7 V12 TDI, VW Touareg V10 TDI, Mercedes-Benz G63 AMG and finally the Land Rover Discovery V8. This list combines both handling and speed. For speed only, the Q7 would be No 3 and the G63 No 4.

Off-Road Performance: The Mercedes G Class is hard-core, closely followed by the Range Rover and the Land Rover Discovery. The Touareg and the Cayenne tie in 4th place (same chassis anyway), followed by the ML Benz.

The Q7 is second last, which would seem strange given the fact that it shares a platform with the Cayenne and the Touareg, but it has a much longer wheel-base and is a lot heavier; and the Quattro drivetrain is slow-thinking, so it cannot quite match up to the other two. Stone dead last is the X6, which is a fashion statement and should be treated as such.

Intelligence: I don’t know what you mean by “intelligence”, but these are all European cars, and they all pack some elaborate forms of cleverness under their bonnets, in their chasses and in their drivetrains.

The vote on engine development would go to the X6, especially the 3.0 litre turbodiesel. Drivetrain and chassis configuration: I’d say the Land Rover Discovery: double chassis, both monocoque and separate, air suspension, Hill Descent Control and the Terrain Response System. All these in one car. None of the others can boast such a feat.

Comfort: It’s no secret: the grandfather of all SUVs, the Range Rover Vogue, with air-suspension, set in Comfort mode, not Sport or Off-road setting. The rest fall into place one way or the other, if they have available air suspension. Some don’t, like the Cayenne. The G Class could be the least comfortable here.

Safety: These are the Euro-NCAP ratings for these vehicles according to the last model tested. Decide for yourself which is which.

Longevity: This depends on how you treat them and where you drive them (and how you drive them where you drive them). The G Class is like a hard rock that will not wear out. The Range Rover’s past history plays against it.

Consumption: If this is the class of cars in which you are looking for your next purchase, don’t ask this question.

But anyway: the diesel versions of these cars will give very good mileage, between 7 and 11 kpl, except the Cayenne diesel (and Touareg) which will still swill till you go shrill. The Q7 6.0 V12 TDI is another case altogether, I’d rather not even talk about it.

The petrol versions of these cars, on the other hand, will bankrupt you faster than those Campus Divas For Rich Men that you see on Facebook. Expect mileages in the region of 4-5 kpl. Worst culprits are the Cayenne Turbo and ML63 (see the rest of the list in the “On-road Performance” section)

The car I’d go for? The Gelandewagen, the Mercedes-Benz G Class, or G Wagon in hip-hop-speak. It looks the part, and in black, with black rims, the G63 AMG’s looks and sounds will ensure nosy neighbours never visit — and they will always lock up their daughte’s whenever they hear Germany’s rudest V8 rumbling into the compound. Class.

2. I did an article on this subject some time back, and it was plagiarised on so many Internet sites that finding it is not hard. Just search “How To Buy A Used Car”… or something like that.

Dear Baraza

I own an old manual Toyota Corolla stationwagon which I am planning to dispose of and buy a newer car. Kindly let me know the advantages and disadvantages of manual and automatic gearboxes before I make my choice.

I want to buy either a Toyota Corolla, a Subaru Legacy or a Subaru Impreza, but I’m yet to figure out the advantages each has over the other in terms of fuel consumption, reliability and performance.

Regards,

Muthoni

Manual transmissions tend to offer marginally better performance and fuel economy, while automatic cars are easier to drive… almost too easy.

Economy and maintenance (and performance) are broadly similar for the Corolla and Impreza (both of 1,500cc). The Legacy performs better than these two but will use more fuel per kilometer and might cost more to keep on the road.

Hello Baraza,

I recently acquired a Toyota Hilux 2007 model fitted with a Toyota 5L 3,000cc engine.

1. What are the pros and cons of this engine?

2. Being new to diesel engines, is this an EFI variant?

3. How does it compare to the Toyota 3L engine in terms of performance and fuel consumption?

4. Would it be wise to change to a smaller engine once the pros and cons are taken into account?

Regards,

Benjamin.

1. Good economy and reliability. Poor output compared to rivals of similar capacity.

2. Yes.

3. The 5L is of bigger capacity (2,986cc) compared to the 3L (2,779cc). It has better power (97 bhp @ 4,000 rpm versus 91 bhp @ 4,000 rpm) and torque (191 Nm @ 2,400 rpm versus 188 Nm @ 2,400 rpm). The fuel consumption depends on use, but the 3L is easier on the drink.

4. Yes. Like the 3L for instance. The differences in outputs (6 bhp and 3 Nm) don’t validate the difference in engine capacity (207cc).

Hi Baraza,
Many thanks for enlightening us through your insightful articles. I enjoy reading them every Wednesday and I have picked loads of tips. Now to my questions: In your experience, what are the common causes of turbo failure and how do you deal with the turbo once it fails? Does it require special care to keep it going?

Kind regards,

Daniel Makau.

Thank you Mr Makau. The common causes of turbo failure are poor lubrication and heat dumping (which is, in a way, the result of poor lubrication). The poor lubrication can either be by using the wrong grade of oil, having low oil levels or thrashing a turbocharged engine as soon as the key is turned.

When a turbocharged engine is cranked, it is advisable to wait for 2-5 minutes (depending on size of the engine and the turbocharger) for the oil to flow around the turbo shaft and into the bearings, and for oil pressure to build up before revving up the engine.

I am sure I do not need to explain the benefits of lubrication whenever metal parts are rubbing together, and in a turbocharger, these benefits are of paramount importance. Turbocharger vanes can sometimes spool at speeds of up to 25,000 rpm. That oil is important.

Heat dumping occurs when a turbocharged engine is turned off immediately after coming to a stop, more so after a period of continuous hard use.

An example is of a bus with a turbo engine charging hard from Nairobi to Mtito Andei before stopping. If the driver feels he must turn off the engine, he should wait, again 2-5 minutes (depending on time period and severity of usage of the engine) before killing the switch.

If the engine is turned off immediately, the oil pump stops working, so oil pressure drops. Poor lubrication. Another thing is that the turbocharger is still spinning at a very high rate, so without lubrication, you can see where the problem lies.

With these high rotation speeds comes heat. The oil that lubricates the turbo also serves to cool it. When the oil stops circulating, all the heat in the turbo is dumped into whatever little oil was left there, and this extreme heat causes something called coking in the oil, where the oil breaks down. Again, poor lubrication.

The 2-5 minute spool-down period thus allows the turbo to slow down and cool a bit before being starved of oil when the engine goes off.

Heat dumping not only damages the oil, but also the turbo itself. On one end of a turbocharger is the impeller, which feeds cold air into the engine.

The other end is the turbine, which is driven by extremely hot exhaust gases. The temperature differential between these two fans is very large, and their only connection is the shaft in between, which bears the brunt of the disparity in heat levels.

With the engine turned off suddenly, heat dumping occurs (rapid drop in temperature), and this sudden loss of heat can cause warping and lead to brittleness of components, which then break. This is the biggest (and costliest) issue with turbochargers.

The best way to deal with turbo failure is to replace the turbocharger unit. Some units are so complex, such as those equipped with variable geometry turbochargers, that opening them up to replace singular components might not be a wise proposition.

Turbos require extra care. Lubrication is of paramount importance. Proper oil grade and levels for the turbocharger, and sober driving techniques are the best palliatives against failure.

Also, let the engine idle a little before applying load on it; and after driving it, give it time to cool down before turning it off. Some cars are fitted with turbo timers which can do the latter for you if sitting in a car for five minutes doing nothing is not your cup of tea.

Hello Baraza,

Thanks for the good work. I own a Volkswagen Golf FSI 1600 CC, year 2006. When I start the engine, it roars very hard for a few seconds then runs quietly.

I have owned a Nissan and a Toyota but have never experienced such noise on cranking. The golf is ‘new’ and I’m the first owner In Kenya. Is this normal? Also, the stated speed of the car online is 197KPH yet my car has the top speed reading 260KPH, is this a fallacy by the manufactures?

Victor Otieno.

The roar could be an excess of fuel being fed into the engine on cranking to prevent hard starts. I am not sure if it is normal. What does CMC say? The speedometer reading is not a fallacy.

The manufacturers tend to use generic speedometers in a lot of their cars. Just because the speedometer has 260 km/h written on the bottom right corner does not mean that car will clock 260 km/h. Have a look at the Premios (first gen) that came in from Singapore. Their speedos also read 260, but that car can barely crack 210.

Hello Baraza

Sir, Toyota is to recall seven million vehicles due to possibly over-heating electric window switches. The recall is for vehicles sold in US, Asia and Europe.

My question is, how would someone in Kenya who drives an import from UK, Malaysia, Japan etc, find out if their car is on the recall list?

Second point: I was told by a Nissan executive that the best source of second-hand Nissans is the UK because the roads there are rough compared to other RHD countries.

UK cars therefore have tougher suspension and reinforced floorpan and suspension points. I drove a UK-built Almeira here for a while and the ride was firm! Your view?

Tony Gee.

To find out if your car is or has been on a recall list (and was actually recalled) is as simple as visiting either the manufacturer’s website or the NHTSA website. There you will find a list of VINs of affected vehicles. Compare it to your own VIN and see if your car is “hot”.

The second point may be true, but remember: UK also salts its roads in winter, and we know salt + water + air =…..?

Rust.

Especially brake discs/drums, wheel hubs, steering arms, etc.

Hello,

I drive a 2005 Volkswagen Golf fitted with an automatic gearbox. The car drives well but has two problems;

1 It jerks when shifting, especially the low gears (1, 2 and 3). A mechanic advised me to change the ATF oil but it didn’t help. Another mechanic told me to change the gearbox but it’s a very expensive affair. What could be the problem?

2. There is a noise on the right front side, at the suspension area, especially when on a rough road. The shocks are new but the whole assembly seems to have a problem. Those are the two issues making me not enjoy the this German technology.

Next time a mechanic tells you to do something as expensive as changing an entire gearbox, ask to explain what exactly is wrong with it and why there aren’t any cheaper alternatives. I have noticed that sometimes these people say things just for the sake of saying. Anyway, here goes:

1 When you changed the ATF, did you fill it up to the correct level? Did you flush the system first before filling in the new fluid? Did you buy a poor brand? Also, check for a leak.

Your ATF could be leaving the car without your notice. Other theories are a clogged filter preventing your transmission from working properly, or a malfunctioning pump and/or a problem with the Line Pressure Solenoid (ask your mech if he knows what this is).

You may not have to buy a new transmission, but if the problem is pressure, cleaning the valve body at the top of the gearbox might solve the issue (sometimes dirt causes the valves to stick and this causes the Line Pressure Solenoid to “malfunction” due to wrong pressure readings).

2. What does that noise sound like? Maybe your new suspension has not had time to bed in, or the fitting was done unprofessionally and there is a bit of play between components.

Hello Baraza,

Thanks for your highly informative articles. I have a Toyota Caldina, new shape. The car runs perfectly, but there is normally a “rotten egg” smell coming from the engine when I drive fast.

I suspected the battery could be the problem and I went to Chloride Exide who recommended an N40 battery but the problem still persists. Please advise me on what to do.
Paul.

The “rotten egg” smell is a characteristic of hydrogen sulphide gas (goes by other strange names such as dihydrogen monosulfide, dihydrogen sulfide, sewer gas, stink damp, sulfane sulfurated hydrogen, sulfureted hydrogen, sulfuretted hydrogen, sulfur hydride…).

From the little chemistry I know, stink damp can be produced when hydrogen gas (common lead-acid battery/accumulator by-product) reacts with molten sulphur.

The sulphur could be from the sulphuric acid used in that same accumulator. Even more worrying is that in that chemical equation, the hydrogen gas could be replaced by a hydrocarbon.

In an automotive engine, the most common hydrocarbon is petrol, though this is a stretch, I don’t see how petrol can reach the battery without human intervention.

The whole process could be cyclic. Sewer gas and oxygen react to form sulphur dioxide and water. In high temperature environments (car engine? I don’t know), the sulphur dioxide and more “rotten eggs” react to create sulphur and water (the Claus Process), and this is probably where the sulphur originated from to create the hydrogen sulphide.

As you can see, this is a self-generating menace right there, because, aside from the bad smell, stink damp is highly explosive.

Anyway, enough of the Chemistry. Why this occurs only when you drive at speed is what is important, and for that I have no answer. It could be something to do with the charging system.

Is the battery being overcharged at high rpm? Maybe. The electrical charging current could be creating undesired electrolysis (the accumulator, is after all, a voltaic /electrolytic cell)

Comments

comments

Leave a Reply