If you want the short answer right now then here it is. You need to keep your tyres inflated to the manufacturer’s exact specifications, swap out your dirty air filter regularly, stick religiously to the service schedule for fresh oil and spark plugs, get your wheel alignment checked if you have hit a pothole, and clear all that heavy junk out of the boot. That is the list. Doing these five things stops your car from fighting against itself. But if you want to know why your bank account feels lighter every time you visit the pump, then we need to get into the details. It is tough enough driving in the UK these days without your own vehicle sabotaging you.
I have been driving for years and I still cringe when the fuel light comes on. It feels personal. We all know that driving smoothly helps, but mechanical issues are silent thieves. They sit there in the background draining your tank while you are stuck in traffic on the M25 wondering where all the petrol went.
This is a collaborative post.
Watch Your Tyre Pressure
This one seems obvious. Yet so many people ignore it. I used to be one of them. I would kick the tyre and think yeah that looks round enough and drive off. Big mistake. Under-inflated tyres increase something called rolling resistance. Basically your engine has to work much harder to push the car forward because the tyres are squashing into the tarmac rather than rolling over it.
The experts say this can increase fuel consumption by up to 5%. That might not sound like a lot on a single trip. But over a year of driving 8,000 miles? It adds up fast. You are literally paying for air that isn’t there.
Do not guess the pressure. You need to look for the sticker. It is usually inside the driver’s door jamb or sometimes inside the fuel filler flap. It tells you exactly what PSI or Bar you need for the front and rear. Sometimes it is different depending on how many passengers you are carrying. I check mine once a month now. It takes five minutes at the garage or you can buy a cheap gauge to keep in the glovebox. It is the easiest money you will ever save.
Let The Engine Breathe
Your engine needs air to burn fuel. It is simple chemistry. If you starve the engine of oxygen it cannot burn the petrol or diesel efficiently. That is where the air filter comes in. It stops dust and flies and grit from getting into the cylinders. But over time it gets clogged up with all that muck.
A clogged air filter is like trying to run a marathon while breathing through a straw. The engine has to suck harder to get the air it needs which messes up the air-fuel balance. This hurts your acceleration and it definitely hurts your MPG.
Replacing an air filter is cheap. You can often buy one for a tenner and fit it yourself if you are handy. If not then any garage can do it in seconds. I changed mine on an old hatchback I owned years ago and the difference in throttle response was instant. It felt like the car had just woken up from a nap. Do not underestimate this small part.
Sticking To The Schedule
I know servicing is annoying. It is a hassle to book it in and it costs money when nothing seems broken. But skipping it is a false economy. Regular servicing ensures your engine is lubricated with clean oil. Old oil gets thick and sludgy. It loses its ability to lubricate properly which increases friction inside the engine.
Friction means heat and resistance. Your engine has to burn more fuel just to overcome its own internal drag. It is a waste. Then you have the spark plugs. If you drive a petrol car these little guys are responsible for igniting the fuel. If they are worn out or dirty they can cause misfires.
A misfire means the fuel in the cylinder didn’t burn properly. You just threw that petrol straight out the exhaust pipe without getting any power from it. It is literally throwing money away. Most modern maintenance schedules are set for every 10,000 to 15,000 miles but if you do a lot of short trips in the city you might need to do it sooner. It is definitely worth checking the manual.
The Alignment Problem
Have you seen the state of the roads lately? The potholes in this country are big enough to swallow a small dog. Hitting a kerb or a deep pothole can easily knock your wheels out of alignment. You might not even notice it at first.
If your wheels are misaligned they are fighting against each other. One might be pulling slightly left while the other pulls right. This creates a massive amount of drag. It is like skiing with your skis crossed. You are not going to glide very well.
You can usually tell if the alignment is out because the steering wheel won’t sit straight when you are driving on a flat road. Or the car might drift to one side if you let go of the wheel. Do not try that in heavy traffic obviously. If the car feels unstable or twitchy get it checked. Fixing the tracking costs a bit upfront but it saves your tyres from wearing out unevenly and stops the engine from burning extra fuel to overcome the drag.
Weight Shedding
We are all guilty of this. You use the car boot as a mobile shed. I once drove around with a bag of potting soil in the back for three months just because I forgot to take it out. Excess weight kills fuel economy.
Physics is pretty unforgiving here. The heavier the object the more energy it takes to move it. For every extra 50kg you carry your fuel consumption increases by roughly 2%. That sounds small but think about what you have in there. Golf clubs? A pushchair you rarely use? Tools? A roof rack you haven’t used since last summer?
Roof racks are a double whammy actually. They add weight and they ruin the aerodynamics. It is like driving with a parachute attached to the roof. Even an empty roof rack creates wind noise and drag. Take it off if you aren’t using it. Your engine will thank you.
Real World Driving
Maintenance is half the battle. The other half is how you actually drive the thing. You can have a perfectly maintained car and still ruin your fuel economy by driving like a maniac. Harsh acceleration and heavy braking are the enemies of efficiency.
I try to look ahead as much as possible. If I see a red light in the distance I lift off the accelerator early and let the car coast. There is no point rushing up to a red light just to slam on the brakes. It wears out your pads and wastes the momentum you just paid for with fuel.
Hybrids are great for this stop-start stuff. Cars like the Mazda 2 Hybrid or the Toyota Yaris are getting ridiculous MPG figures these days especially in town. But even in a standard petrol or diesel car being smooth makes a massive difference. I think patience is probably the best fuel-saving device you can install in a car.
A Word On Hybrids
Since we are talking about maintenance it is worth noting that hybrids and EVs have different needs. They still have tyres and suspension that need checking. In fact because EVs are heavier due to the batteries they can chew through tyres faster if you aren’t careful with the pressures.
Plug-in hybrids are interesting beasts. You can get incredible mileage if you keep them charged. The stats for cars like the Mercedes C 300 e are mind-boggling on paper. But if you never charge it and just run on the petrol engine you are basically hauling a heavy battery around for no reason. That goes back to the weight issue. You have to use the tech properly to get the benefits.
The service intervals might be longer on some of these newer cars but the basics remain the same. Keep it clean. Keep it lubricated. Keep it straight.
Final Thoughts
It is easy to ignore car maintenance until something goes bang. I get it. Life is busy and mechanics are expensive. But ignoring these small things is a slow leak on your finances. You don’t notice the 5% here or the 2% there but over a year it could be the difference between a weekend away or just burning that cash in traffic. Combining these maintenance habits with a steady right foot is the best way to keep your costs down. And of course it never hurts to check fuel prices in your local area before you fill up because paying 5p more per litre just because it’s convenient is painful. Take care of your car and it will generally take care of your wallet. Usually.