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THIS WEEK: when cold weather puts the brakes on and a Prius’s mpg

THIS WEEK:when cold weather puts the brakes on and a Prius's mpg

 From BN: For two successive years, while my wife and I took winter breaks overseas, our car had to be left outside, unused for some weeks. On returning, the car was immobile as the breaks had locked on all four wheels. (The handbrake was intentionally not engaged during the period of our absence.) On the last occasion, all four wheels were so tightly locked that the car had to be winched forcibly, with slides under the wheels, onto a tow truck for repair. I was informed that, when left unused for some time in winter conditions, the brake shoes can lock themselves to the discs due to a layer of corrosion building up. I wonder if other drivers have experienced this problem and what measures can be taken to prevent it happening.

For help with your problem we turned to AA Ireland’s technical department, which tells us that it’s an issue that can arise with any car to a certain extent and there’s little that can be done to avoid it happening when leaving a car unused and exposed to the elements. “

The type of seize-up described is rare but can happen. It would take a proper investigation of the car to diagnose the particular problem in this case, but we have had extreme weather in the last year. Regular use helps prevent this, so if this reader is unable to keep the vehicle indoors, perhaps asking a neighbour to take it out for a drive (30-45 minutes minimum) at least once a week would help avoid the build-up of corrosion that causes this issue.” Have other motorists encountered similar problems and if so with what cars?

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From MP: A few months ago you wrote about hybrid cars and mentioned that the Toyota Prius doesn’t always do the miles per gallon claimed. My son-in-law bought a second-hand Prius a few weeks ago: a lovely car. On the motorway, doing steady driving, it’s only managing 49 miles per gallon. He’s a bit disappointed so I said I would see if you’d give an opinion.

Few cars manage to match the official figures, which are achieved under very specific circumstances that aren’t easily replicated in real life. In large part the figures are meant to be a direct comparison – all other things being equal – and they let consumers judge which cars are better or worse than their counterparts. In this regard the Prius does relatively well, and if he is getting 49 mpg in it, what might he be getting in a similarly aged rival car for the same money? The simple fact is that with the Prius, you reap the most benefits at lower speeds and in town traffic, where the car’s electric motor plays a more active part. Out on the motorway or at main road speeds, if he is in any way heavy on the accelerator he’s effectively driving it on the petrol engine, and getting the consequent fuel economy. If he spends a lot of time on motorways and doesn’t do much driving in traffic then he would probably be better off with a modern fuel-efficient diesel.


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