EXPLOREMY LIBRARY
Cars & Motorcycles
Car Mechanics

Car Mechanics

October 2020

Car Mechanics is the UK's only car magazine with essential advice on maintaining and repairing popular makes and models. It’s an invaluable motoring resource that appeals to both the DIY car enthusiast and the more experienced motor trade professional. Car Mechanics has helped save money for our readers every month since 1958. Each issue includes a wide range of in-depth features written in a clear, straightforward manner: • Readers’ motoring-related problems answered for FREE • Real-life motoring dilemmas from our man in the garage trade • Electronic diagnostics delves inside a different modern vehicle each month to explain its management system • Survival Guide looks at new and used component prices for a particular vehicle • Used Car Focus is an in-depth buying guide on a specific make and model • Service Bay covers a full service with close-up images and comprehensive descriptions • Project cars are a major part of the structure of the magazine as we buy, fix and sell different vehicles over a period of months So if you're into saving money and being a home technician, Car Mechanics will help you out - guaranteed!

Country:
United Kingdom
Language:
English
Publisher:
Kelsey Publishing Group
Frequency:
Interrupted
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in this issue

3 min.
editorial

Email martyn.knowles@kelsey.co.uk Follow us on Facebook @ Car Mechanics Do your checks I was made aware recently of something that might catch you out. It’s to do with the MOT exemption that we had earlier in the year in England, Scotland and Wales. You may remember the government announced that from March 31, 2020 all cars that were due an MOT could, if appropriate, delay the MOT Test by six months. Then in June it was announced that the six-month extension was to be shorten to four months. That meant any vehicle due an MOT Test after August 1, 2020 would return to its mandatory annual inspection from that date. Those vehicles that are running around on the six-month extension will have MOT expiry dates from now to the end of January 2021. That’s…

14 min.
engine oil

Even in today’s supposed ‘eco-friendly’ world, the link between the modern motor car and the petrochemical industry remains unbroken. From most interior plastics to the fuel that still powers over 98% of cars registered on our roads, perhaps the most obvious link to fossil-fuel is the engine oil. Planes, trains and automobiles Whether mineral oil, intended for a four-pot classic, or a sophisticated synthetic lubricant for a modern direct-injected turbocharged triple, the ‘base stock’ originates from crude oil. Yet, while nature provides the raw material, humans deliver the development. Petroleum-based mineral oil was less prone to solidifying when cold and leaving fatty deposits behind at higher temperatures, compared to animal and vegetable oils, making it more suited to the harsh environment of an internal combustion engine. Yet, the raw product remains from…

1 min.
new oil standards – europe lags behind

► While API standards are general indicators of quality, they are not intended for European and British markets, unlike those of the ACEA. To provide a temporary means of addressing problems that were afflicting GDI engines in particular, API introduced ‘SN Plus’ in May 2018, as an update to the pre-existing ‘SN’ specification, which gave breathing space to develop a new standard. The result is API SP, introduced formally in May 2020. Interestingly the ACEA has delayed introducing similar specifications; they were intended to be introduced during 2018. We contacted the ACEA and did not receive an explanation, prior to going to press. All we can recommend for GDI engines is that you choose an oil based only on the manufacturer’s recommendations. If you own (or maintain) a very young car, especially…

2 min.
what engine oil does

Without a suitable lubricant, an internal combustion engine would not last for long. A complete loss of oil pressure results in the heavily-loaded metallic components to contact, overheat and seize. Many parts of an engine have different lubrication demands than others and the main practical issues affect classic car owners, where certain anti-wear additives that protect older engines are either reduced, or removed, for environmental reasons. However, this does not always mean you should pay a premium for oils with these additives put back in: ZDDP (Zinc DialkylDithiophophate) is a typical example. Aside from preventing metal-to-metal contact, the oil must also transfer and shed heat effectively. However, this and lubrication are not its only roles. Certain components rely on the pressurised oil to provide an hydraulic function, such as valve lifters,…

1 min.
how engine oil deteriorates

Oil does not last indefinitely within the hostile environment of an engine. Its molecular structures are torn apart by the oil being squeezed constantly between moving metal surfaces, such as the crankshaft bearings/crank pins and the cylinder bores/pistons. Eventually, this reduces the viscosity so that the oil film strength is compromised. Heat also destroys the lubricant’s effectiveness on a molecular level. With modern petrol engines running at higher temperatures, the oil risks premature oxidisation and certain elements vapourising under the intense heat. Additionally, just as oxidisation causes food to go bad, oil’s natural interaction with atmospheric oxygen causes chemical degradation that not only affects the viscosity but also leads to reduced protection against deposits. While the engine oil is designed to become dirty, the contamination must not drop-out of suspension. As…

1 min.
oil temperature

Even the latest design of engine has an ideal operating temperature for optimum efficiency, which is why the latest cooling systems boast sophisticated on-demand water pumps to speed the warming process. While most cars possess a coolant temperature gauge, many drivers do not appreciate that the oil takes longer to heat up to its ideal temperature – of around 80°C. Oil temperature is dependent on load. Sustained long motorway runs, or driving that involves high RPMs and hard acceleration make it run hotter. Should the oil overheat, its viscosity can drop excessively, risking increased metal-to-metal contact, as well as various constituents within the oil vapourising and depositing residues within the crankcase. On many modern cars, most of which lack either an oil temperature gauge/warning lamp (such as that pictured right), an oil…