Technical Queries

How to test battery health


  1. Posted on January 7th, 2019 by Rob Marshall
  2.   Several GEM members have called our technical helpline recently, asking why a battery that has a healthy voltage can seem to be unable start an engine from cold. A voltage test does not tell the whole story and this is why:   State of Charge vs. State of Health Taking a voltage reading will […]

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Will your car make you ill?


  1. Posted on December 11th, 2018 by Rob Marshall
  2. According to Volkswagen Commercial Vehicles, drivers are at risk of breathing-in allergens that are trapped in vehicle cabin filters, after the summer’s pollen count hit a 12 year high between late-March and early-September.   Cabin filters, also called ‘pollen filters’, prevent a variety of particulates from entering a vehicle’s interior. This ranges from seeds and […]

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Why you need to replace old HID headlight bulbs


  1. Posted on December 4th, 2018 by Rob Marshall
  2.   One of the many advantages with High Intensity Discharge lamps, as opposed to filament bulbs, is that they last longer – or so we thought. As more cars have been equipped with them from new, it has been noticed that, while HIDs do not fail suddenly like a traditional filament light bulb, their output […]

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Brakes become top killer defect


  1. Posted on November 30th, 2018 by Rob Marshall
  2. According to the Department of Transport, mechanical defects caused 1,539 road traffic incidents last year, leading to 359 serious injuries and 32 deaths.   Faulty brakes accounted for 570 accidents last year, 129 serious injuries and nine deaths, eclipsing defective/ill maintained tyres as the second highest mechanical defect.   Lack of Access The main problem […]

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Sensors lead the way in warranty claim


  1. Posted on October 29th, 2018 by Rob Marshall
  2. A report that says sensors have pipped alternators to become a top warranty claim (for those sold by the RAC dealer network) came as little surprise to us, when the news hit GEM’s technical helpdesk. There are several reasons for this, such as virtually everything mechanical being influenced, or controlled, entirely by electronics that depend […]

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Why has re-gassing air conditioning become so expensive?


  1. Posted on August 10th, 2018 by Rob Marshall
  2. We have received members comments on how air conditioning regassing has become considerably more expensive, especially during this summer. While you could be sceptical and comment that unscrupulous garage owners have bumped-up their prices during the summer heat, the truth is somewhat different. Saving the planet or an air ‘con’? Air conditioning gas is a […]

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New diesel engine that runs on petrol announced


  1. Posted on July 17th, 2018 by Rob Marshall
  2. With the considerable anti-diesel rhetoric that exists currently, one would think that the world had turned its back on compression-ignition engine technology. That is untrue. While new UK sales have declined, demand for used diesel cars has risen. One of the major issues is that there is no realistic alternative to heavy-oil cars, on the […]

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Dangers of (under) inflation


  1. Posted on July 10th, 2018 by Rob Marshall
  2. While many road safety bodies, including GEM, emphasise the importance of correct tyre pressures, it is worth making additional pressure adjustments during the holiday period, particularly if you are planning long-distance trips.   Relating tyre pressures to weight If your car spends much of its time lightly-loaded, it is likely that your tyre pressures will […]

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Automatic gearboxes – preventative maintenance


  1. Posted on April 26th, 2018 by Rob Marshall
  2. While modern automatic gearboxes have evolved considerably since the 1980s, they still require to be looked after. Following this general advice will help your automatic transmission last for as long as possible. Getting your definitions right The advice given applies to the ‘traditional’ format automatic gearbox, with an epicyclic drivetrain and torque converter clutch. It […]

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Tyre ageing to be researched


  1. Posted on March 28th, 2018 by Rob Marshall
  2. It is a popular question among GEM members – when does a tyre become too old? Sadly, we cannot provide a definitive answer, because it depends on so many variables, including storage and usage conditions. Whenever we have queried premium tyre manufactures about age limits, the answers are, understandably, vague. Research commissioned Yet, the first […]

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