Mechanics share their driving tips to help you save money on car repairs

Almost all of us think we’re good drivers but mechanics will tell you that the evidence says otherwise

Welcome to this week’s On The Money, which marks one year since we first sent this newsletter. During that time we’ve covered a range of topics from consumer rights and making a will, to pensions, mortgages and solar panels and many more besides. We’ve even shared the secret to a happy marriage. You can read back on all of our articles here, sign up to receive this weekly newsletter straight to your inbox here, and if you have a personal finance question you would like us to address, just contact us at

This week we looking at the cost of car repairs. Think you’re a good driver? The amount of money we spend on avoidable car repairs and repeat NCTs when our car fails tells a different story – just ask a mechanic.

Here are mechanics’ top tips on how to save on the car repairs they see every day that are totally avoidable, if only we could all just drive our cars properly.

Buy the right car

Buying a car that doesn’t match your needs can be a costly mistake. “If you are looking for something to do the school runs and a shop, there is no point in buying a big diesel,” says Derek Reynolds, workshop controller at Dooley Motors, a long established new and used car dealership in Carlow town. “For that kind of thing, you’ve got to stick to hybrid or petrol.”


The big diesel cars, with 1.6 litre to 2.2 litre engines are made for driving. If you use it as a runaround, you’ll pay for it in repairs.

“A lot of drivers aren’t aware of the way to drive their vehicles in order to carry out regeneration, which is like a cleaning process of the diesel particle filters,” says Reynolds. Your car needs to be driven a particular way for this to happen – otherwise the exhaust can get blocked.

“You need to drive your vehicle for 15-20 minutes at over 2,000rpm [revolutions per minute] for that process to take place,” says Reynolds. That means hitting the motorway, usually dropping to a lower gear. The speed and gear aren’t the important thing, he says, just check the clock on your dash, the one beside the speed clock, to make sure you are over 2000rpm.

“Do that for 15 minutes without interruption,” says Reynolds. “We find a lot of people miss out on this threshold with the types of journey they are doing.”

If your car doesn’t get a chance to drive like this, things will block up. “Diesel particle filters can cost anywhere from €600 all the way up to €2,500 and €4,000,” says Reynolds.

“I don’t l know if it’s a status thing with people, but there is really no need to be going with the big 2.2 litre diesel if you are only tipping around.”

Speed bumps

If you’re the kind of driver who tackles a speed bump like B.A. Baracus from the A-Team, your mechanic can spot it a mile off.

“Absolutely, you can tell if a car is being driven roughly over speed bumps,” says Reynolds. The damage caused is much the same as hitting a pothole at high speed.

The jolt can cause issues with alignment, suspension, shocks, and tie rods – all of which means money. “Shocks in a main dealer could be €200 plus VAT, with another €100 for fitting,” says Reynolds. Damaged track rod ends will cost about €60 and tie rods up to €80, plus labour. Then you’ll have to get your wheels realigned.

Suspension is critical to your car’s handling and braking. Indeed, an imbalance of 30 per cent or more between the suspension on the left and right side of your car will result in an automatic NCT failure; so too will evidence of wear, leaking, cracking or other significant damage.

Indeed, after tyres, front suspension was the second most common car defect, according to NCT figures. That’s €55 down the drain on an NCT you will fail and another €28 for a retest. Slowing down over speed bumps will add seconds to your journey but can save you hundreds.

In gear

When approaching traffic lights or a roundabout, how do you slow down? If you are hitting the brakes instead of changing down gears, that’s costing you money. Slowing down with your brakes, not your gears uses more fuel and will wear down your brake pads – another pricey fix.

“Try to engine brake instead. It is more fuel efficient as the engine returns the unused fuel back to the tank,” says Matt Davies of Windsor Clonee. Engine braking is the process of slowing down by stepping off the accelerator and downshifting gears instead of pressing on the brake pedal.

“The harder you jam on the brakes, the hotter the brake discs are going to get and they get more wear faster. You could be looking at anything from €400 to €480 for a set of front brake pads and discs,” says Derek Reynolds.

“You should be approaching a roundabout or traffic lights in third gear and dropping to second,” he says.

Start me up

Proud of your speedy reverse parking skills? Not so fast. Whizzing into reverse too quickly is damaging your gears.

“When changing from first gear to reverse and vice versa during park manoeuvres, make sure to wait a few seconds in between and ensure the car is stationary to avoid damage to the gearbox components,” says Davies. “Gearbox repairs often run into the thousands.”

When you start your car, allow a few seconds for the engine to settle into a normal idle before beginning your journey, says Davies. This will also avoid unnecessary engine wear and strain.


Checked your oil levels recently? Failing to keep them topped up can cost you thousands of euro.

“The number of cars we see with low oil level warning lights on is just silly,” says Davies. “Low levels of oil can lead to internal engine damage and premature wear.” Choose the right oil for your car too. Using the wrong oil on engines that use belts that run in oil is a costly mistake. “Repairs are anywhere between €5,000 and €15,000, maybe more,” says Davies.

Under pressure

Checking tyres is among the easier thing a motorist can do. Or maybe you were just hoping that warning light on the dash would disappear. The wrong tyre pressure can cause premature wear of tyres and if the tyre pressure is too low, you’ll end up using far more fuel. The wrong tyre pressure means poor road holding too, so it’s dangerous.

Problems with tyres, including mismatched tyres, worn treads, visible damage and tyre pressure, is the most common reason for NCT failure.

Tyre pressure and the type of tyre you use on electric vehicles and hybrid cars is even more important, says Davies. Low rolling road resistance tyres can be particularly suited to these vehicles as they can reduce energy loss, improving vehicle efficiency.

Warning lights in general should not be ignored. Find out what they mean before you start driving and find out what fluids go where. Read the manual or ask the dealer to explain things to you.

“Some dealers might fob you off, but if they are selling you a car and can’t be bothered to help, then they are not worth the money,” says Davies.


Do you gamble with the fuel light, trying to squeeze an extra 10km out of the tank before filling up? Apart from leaving you stranded, running too low on fuel can mess with your fuel gauge, costing you a trip to the garage that could have been avoided.

“Extremely low fuel levels can lead to engine warning light illumination which may require a dealer visit simply to turn it off,” says Davies. “Also, adding fuel amounts lower than 10-12 litres each time can cause the fuel gauge to operate erratically.”


Got frost on your windscreen? Don’t use your wipers to clear it, warns Derek Reynolds. Damaging the rubber on the wiper blade will be the least of your troubles – though it can cost up to €70 for a new set for an SUV or people carrier.

“We get a lot of people in frosty conditions who come in with a fuse blown in the wiper motor because the motor is trying to move the wipers and it can’t. That fuse is just 50 cent and we won’t charge you for fitting it, but if you damage the motor, you are looking at €300 to €500 for a new wiper motor,” says Reynolds.

De-icer can damage wiper rubber too. It’s best to switch the heat to a middle setting and slowly defrost the windscreen.

“Lashing the heating on, hot straight on to cold, as it’s defrosting, you’ll find a crack in the windscreen. And that’s from personal experience,” says Reynolds. If you’re in a rush, some lukewarm or even cold water on the windscreen will do the job.


One final tip. We’ve all seen the images of cars driving through floods on roads. There have been far more flooded roads recently and that’s likely to continue. “My personal rule of thumb is if you open your door in flood water and it comes into the car, then it’s a bit too deep to drive through” says Matt Davies. Yet, people drive through high flood water.

“Water and the air intake of an engine don’t mix. This usually results in engine replacement and it’s very costly.”

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