Car owner behaviour that leads to engine oil leaks

A mechanic performing a routine service inspection. PHOTO | FILE

What you need to know:

  • Here I was thinking oil leaks are caused by wear and tear of sundry seals.

Dear Baraza.

Have you ever seen a fresh import with an engine oil leak? I’ve never seen any, so why do oil leaks develop in Africa?

Well, most oil leaks are caused by higher oil pressure than required. We need to understand what controls the oil pressure. Ideally, there should be an oil pressure valve somewhere along the oil circulation system, but where?

In nine out of 10 engines you’ll find the oil pressure valve in the oil filters. Here is where we go wrong. We buy cheap filters that don’t have the valve, therefore resulting in high oil pressure. Many times we fit oil filters that just fit, not caring which engine it was designed for.

This too can make an interesting read. Thanks

Hmm. Interesting. Here I was thinking oil leaks are caused by wear and tear of sundry seals and gaskets occasioning from age and/or overuse.

I am aware that overfilling of oil does happen, but I have only seen this in the world of motorsports, I am yet to witness it in ordinary cars.

But then again, I don’t work in a garage, so the odds of my coming across such an occurrence are slim to none.

We will refrain from cracking any Land Rover jokes as far as oil leaks go, but take note of the lesson anyway, which I gather is the need to buy legitimate parts for your cars (oil filters in this case), something that seems painfully obvious at first sight but clearly needs retelling.


I have visited several motor vehicle assembly plants, including GM’s in Port Elizabeth South Africa, and I must say I agree with their taking exception to having their work trivialised into mere “cobbling” of kitchenware rather than the expert engineering that it actually is. Their response was a long time coming, but it is here anyway.

I have changed nothing, and leave any adjustment to the discretion of the editor.

Dear Justus Baraza,

Thank you for your insightful article on local vehicle Complete Knock-down (CKD) assembly. Your reviews on the local automotive industry are always refreshing and constructive.

Isuzu EA wishes to shed some light for the general benefit of your readership on an issue raised by one of your avid readers in your article, ‘Aren’t vehicle assembly lines simply DIY projects where well measured CKDs are cobbled together to make a complete unit?’, published in the Daily Nation of April 22, 2020.

 Our attention was drawn to the reader who sought clarification on the Isuzu manufacturing process. In his query, he attempted to equate motor vehicle assembly of CKDs to Do-It-Yourself (DIY) kits, averring that it was akin to disassembling a kitchen mixer and then cobbling it back together again.

The definition of DIY literally means the activity of decoration or making repairs at home by oneself rather than employing professionals. Manufacturing, however, is the making of goods by hand or machines using raw materials or components of a larger product with a view to sell to a customer.

Manufacturing usually happens on a large scale on a production line using machinery and skilled labour to satisfy demand in a market. As you rightly pointed out to him, it is important to note that the vehicle assembly at our plant is miles apart from DIY projects. Whereas a typical DIY kit would need a one-page instruction sheet, a basic screwdriver and at most a pair of pliers, vehicle manufacturing involves dozens of specialised processes handled by highly skilled and trained personnel.

Thus based on this global understanding, the CKD vehicle assembly is the end stage of a vehicle manufacturing process since some critical components of the vehicle, the engine and transmission, amongst others, usually would have been manufactured and pre-assembled at different sites before they are shipped for final coupling at an assembly plant. This is a very common concept applied across various industries including aircraft, motorcycle, computer and cellphone manufacturing companies.

To further demonstrate the difference between DIYs and manufacturing, a production line requires hundreds of parts, some of which we source from local suppliers. These include vehicle seats, harnesses, exhaust pipes, leaf springs, U-bolts, cross-members, paints, batteries and tyres.

The CKD motor vehicle assembly in Kenya is guided by various regulations, including the Customs & Excise Tax Act on motor vehicle assembly, Kenya Standard (KS) 372:2014 on bus body building and the National Automotive Policy of 2019. The latter clearly defines the various levels of CKD assembly authorised in Kenya as well as what components or parts are to be manufactured locally.

The level of skilled professionals on the vehicle assembly lines ranges from technicians to engineers and researchers to ensure there is continued improvement and adoption of new technologies. This is something your average DIY enthusiast has no need or capacity to do.

In addition to the local cabin and chassis assembly process, fabrication of bus and truck bodies is subject to stringent standards set by the Kenya Bureau of Standards (Kebs) to ensure quality is maintained amidst the aesthetic appeal and finesse used to attract passengers as evident in the public transport sector.

It is fair to accept that technology keeps changing. Whereas the use of rivets in body building for buses in the past may have had its adherents as pointed out in your column, the use of modern technically advanced welding has gained its place in the auto industry. Today, previously unthinkable modern adhesives are being used to bond body parts of high-end luxury cars, while their engines are made of aluminium alloys as opposed to steel for reasons that you may have covered before.

As opposed to the Do-It-Yourself projects, the nature of the vehicle manufacturing industry requires a lot of advance planning and holding of various inputs and raw materials that can last months at time. Hence the need for assemblers across the world to occupy large spaces to accommodate storage of these raw materials, the production lines and have adequate storage of the finished vehicles, not to mention space for expansion of facilities.

The man is right, making cars is hard. It is unfortunate that all our factory visits are punctuated by strict instructions not to engage in any photography and, hard as it is to make cars, it is even harder trying to describe a factory floor or assembly line using words only.

You need pictures as well, but that won’t stop me from trying anyway.

There is a lot of robotised stuff, as is to be expected, but invariably, human input is critical. The man-machine ratio varies from one manufacturer to another as do various internal affairs such as work ethic and trade practices, but skill and ability are paramount.

Some makers such as Iveco have their workers rotating from one workstation to the other week after week while others like General Motors’ Port Elizabeth plant prefer one specialise in one thing and stick to it. I think it saves them on training fees or something.


Isuzu’s definition of what makes a good bus body may differ from mine - I’m still not sold on the work of local fabricators - but there is a stance I would encourage them to adopt in an effort to raise standards collectively, something their own competitors at DT Dobie did with one of their products (the MB1730 bus): be choosy about who dresses your chassis and who doesn’t.

The good people at Mercedes-Benz came up with a list of preapproved fabricators who are allowed to fit bodies onto their chassis and there were some notable omissions from that list and with good reason: some of these bus builders have no pride in their work and are the kind of fellows who inspire my readers to compare motor vehicle assembly to self-taught kitchen repair regimes.


Four questions on CVTs answered

Oga JM,
Allow me to knock your head around CVTs and see what falls off. I understand the basic science around Continuous Variable Transmissions and the pros thereof. However, the consensus around town is that CVTs are unreliable. I think this is due to our mechanics’ fear of new tech and mental inertia that has resulted in this conclusion. That notwithstanding, help answer the questions below:

 1. How often should the CVT transmission oil be changed? How do you ensure you fill up with the right oil considering we are in the tropics?
 2. What are the telltale signs of a failing CVT? In case of failure, is it advisable to repair or to just get a new unit?
 3. What is the use of the manual gear selector in CVTs? How does a gear-less set-up shift gears?
 4. Is it true that Mazda has no CVTs in its entire line-up?
Looking forward to hearing from you,

Hello Ithiga,
We had someone demystify the root of CVT problems affecting Nissans in particular last week, and I must say it was quite the eye-opener. Turns out ABS issues can affect the transmission. Who'd have thought?

1. Change of CVT should be according to the manufacturer's recommendation. Some of these gearboxes require routine maintenance while others are sealed for life. Reading the owner’s/operator’s manual should clear the air on this.

2. Signs of failure? Well, from last week’s input, a flashing ABS light is one of them. Fluid leaks are another, as are vibrations and unresponsiveness. Sometimes a burning smell can be observed as your gearbox slowly dies on you. The debate between repair and replacement will depend on how critical the condition of your CVT is.

3. I once did an elaborate explainer on how CVTs work and while they lack individual gears, they use a belt and pulley set-up to create an infinitely adjustable range of gears. The gearbox can be programmed to have virtual “gears” at preset points along the variation, giving the impression of discrete gears which can then be manually selected. Subaru does this.

4. Yes, Mazda does not dabble in CVTs, because they don’t believe in them, which is very interesting. They say a regular automatic makes for a better driving experience and durability at lower cost, which is more important than the fuel economy gains provided by CVTs. I may not know about the costs and durability, but I agree with them about the drivability of a CVT versus an auto.