How can I know the right engine oil for my car?

Autos & Motoring

Last Post by S. M. Lawal 7 years ago

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S. M. Lawal

Joined: 7 years ago

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Topic starter February 28, 2018 11:24 am

I ran into a female car owner who, recognising my “bearded face” from “that PUNCH motor column,” asked me the question that’s improvised above as the headline of today’s piece.

I must confess that I was a bit melodramatic in my response to her: I asked to be given any engine oil plastic container around. Once that had been secured, I then started by stating and explaining the chief criterion that must be established in getting the right specification of engine oil: first, identify the particular engine oil specification that your car/vehicle’s engine manufacturer has recommended to be used in its engine.

“Engineer, how can I know that — what my manufacturer says I must use?” “Easy,” I retorted. If you open your vehicle’s bonnet/hood, there’s a particular channel where the engine oil is poured down through to the automobile’s engine. Atop that channel is a cap (which is usually screwed off by hand before oil is poured through the channel and screwed manually back after pouring the oil). In most vehicles from the US, the oil spec appears in large lettering on the oil channel’s cap; usually starting with SAE (Society of Automotive Engineers), which is then followed by either a numeral ‘0’ or ‘5’ or ‘20’. Any of these three first stated numerical figures is automatically followed by a ‘W’; which literally means that at either ‘0’ or ‘5’ or ‘20’ — depending on what exact number is written immediately after the ‘SAE’ first on your engine oil’s plastic package — and above ‘weather’ temperature, the oil in the container will still retain its fluidity or liquid status. Any weather condition with temperature below that number specified before the ‘W’, the oil’s chemical composition will likely congeal and make it, while parked for some time, lose its liquid or fluid status!

It should then be obvious to anybody reading this article that, because our weather/temperature conditions seldom fall below 20 degree Fahrenheit (except occasionally in places like Jos, Plateau State, or on the famous European-type cold weather conditions of the Mambilla Plateau in Taraba State), the initial numerical figure, especially if it specifies ‘0’ or ‘5’, shouldn’t be of concern to a motorist trying to buy the right engine oil in Nigeria. Not even the coldest point in Nigeria goes as low as 5 or 0 degree Fahrenheit; I doubt if there’s even any location in Nigeria as low as 20 degrees Fahrenheit. 20 degree Celsius? Maybe, yes. Celsius is hotter than Fahrenheit.

However, the number after the ‘W’, usually either a ‘20’ or ‘30’ or ‘40’ or ‘50’, is the most important in Nigeria: it’s the number that defines the viscosity or thickness of the oil. Why does this matter? If, for example, the manufacturer states ‘20’ after the ‘W’ and any of ‘30’ or ‘40’ or ‘50’ were to be used, because each one of these three grades of viscosity is thicker than the ‘20’ recommended, the oil will not likely get efficiently to the nooks and crannies of the engine! The internal capillaries of the modern automobile engines are very finely cut. Oil with thicker fluid characteristic, if often used, will inevitably cause sludge to build up inside the engine. And that’s a sure fast way to getting the engine knocked. In fact, you will be wasting money on fuel and you will be polluting the environment before the engine finally hooks.

It’s also very important to state the reverse side of the viscosity scenarios: if the manufacturer states that a higher viscous oil, say, ‘50’ be used and ‘40’ or a lower rate of thickness is used, the speed of wear and tear on the internal walls and the moving parts going up and down the walls will be faster! Why? Amongst other functions like detergence (the cleansing effect of lubricants), etc., the fundamental purpose of lubricity (which protects the metal surfaces from early wear) is achieved through the film of oil that protects the metal surfaces from bruising friction. If the viscosity of the oil is lower than specified by the manufacturer, that protective film will be thinner than it’s expected to be at the design and test stages. And wear will be faster.

Once any engine oil’s package doesn’t match the exactitude of the last numerical figures after the ‘W’, please don’t buy it. There are other criteria that can be used to adjudge the quality of an average engine oil, but the primary consideration is the SAE spec. Should you need any further enlightenment on this subject or any other that will make you get value for money from your vehicle, you can always call our interactive voice response corporate social responsibility number: 01-4406666.

Feedback
My 2006 Honda City has been overheating for weeks now. The auto mechanics and electrician suggested connecting the fan blades directly (to blow continuously) and removing the thermostat, but the problem persists. Aside from this, the car runs smoothly. Please, your expert advice would be much valued. Thanks. —Adeniyi Seyi (Ibadan)

I believe a cooling test needs to be carried out on the cooling system. Overheating is just a symptom; something caused the system to overheat. They need to find out if any of these parts caused the problem: fan, thermostat, water pump, clogged or leaking radiator, missing fan shroud and lastly a blown head gasket.

I have a 2007 Lexus GX 470. Recently, I observed some noise from the rear of the vehicle while in motion. Please, what could be the cause of the strange noise? There’s no warning light showing on the dashboard.

I have a feeling the noise is from the suspension parts. The fault can be diagnosed by driving and also doing visual inspection on the rear suspension.

My name is Mr. Victor. I bought a used Ford Grand Caravan and had some repairs done by a mechanic workshop at Maryland, but it seems the mechanic is doing guesswork, because the automobile does not start promptly. The electrician is asking for N32,000 to repair the fuel gauge.

To start with, there is nothing like a Ford Grand Caravan. Only Chrysler makes the Grand Caravan. You didn’t specify the type of electrical work that was done on the van, but what I can tell you is that the electrician will determine what he needs to charge for the repair.

Diagnostic codes

P040A – Exhaust Gas Recirculation Temperature Sensor ‘A’ Circuit

The Engine Control Module (ECM) monitors the Exhaust Gas Recirculation (EGR) Temperature Sensor ‘A’ Circuit Performance, which measures the temperature of the exhaust gas. The EGR Temperature Sensor functions by increasing the resistance with increasing exhaust gas temperature. The ECM sets the OBDII code when the EGR Temperature Sensor signal is not to factory specifications.