Tips Improve MPG keep old diesel car running

Tips to keep your car running smoothly while maintaining performance and improving MPG. My reference vehicle is a 17-year-old 2009 Vauxhall Insignia with 172,000 miles, achieving around 60 MPG and still driving like new!

My 2009 Insignia with 172,000 miles on (Sept 2026)

Here in the UK, fuel currently costs around £2.00 per litre. For my American friends, that's approximately $10.22 per US gallon! I chose my car because it was affordable—I paid £2,000 for it five years ago when it had about 90,000 miles. It's easy to maintain, offers excellent MPG, and has ample boot space, making it the perfect motorway cruiser!

One of the easiest and completely free ways to improve your MPG is to reduce weight. Remove any unnecessary junk from the boot, as carrying extra weight means the engine has to work harder.

If you have roof bars fitted, consider removing them when you’re not using them. They create additional aerodynamic drag, which can increase fuel consumption.

Tyres are another important factor. Make sure they’re inflated to the correct pressure, and if you’re in the market for a new set, use the tyre labels to look for A or B-rated fuel efficiency.

Personally, as a high-mileage driver, when I’m choosing to buy a car, the cost of getting from A to B is one of the most important factors I consider.

Major Car Service at home

Fuel additives! I'm a big fan of Liqui Moly which is a German company and I use their products in lots of my YouTube car repair videos and 3-4 times of the year I use the "Liqui Moly Diesel System Cleaners" (Amazon Link) It's easy to use you just put the whole can into your fuel tank and that's it. It treats up to 70 ltr of fuel so I usually wait until I am 1 line away from being empty, put the can in and drive to the fuel station and fill up half a tank. I hover around 55-60mpg on average! Which is simular to what the car was new (spec)

Adding a can of Liqui Moly system cleaner

It is designed to:

• Clean diesel injectors/nozzles and remove deposits that can affect fuel spray.

• Clean deposits throughout the fuel system and combustion chambers.

• Help prevent injector needles from sticking or gumming up.

• Improve fuel atomisation and combustion.

• Reduce diesel knocking/rough running caused by deposits.

• Help restore the engine's original performance where deposits have been contributing to reduced performance.

• Provide corrosion protection and help reduce wear.

• Potentially reduce smoke and emissions where dirty injectors are contributing to them

Car Service. On my YouTube channel (Clickable Link) I have a play list which you can use as a guide. 🔧 What's Included So Far:

✅ Major DIY Service – How to change air, oil, and cabin filters (#ChangeFilters)

✅ Coolant Tank Replacement – How to replace a car expansion tank

✅ Starter Motor Replacement – Step-by-step fix for starting issues

✅ EGR Valve & Throttle Body Cleaning – Restore engine power

✅ Brake Replacement – How to change Vauxhall Insignia brakes (#Brembo)

✅ Car A/C Fix – Troubleshoot and fix aircon blowing hot air

✅ K&N Air Filter Cleaning – Maintenance for performance filters

✅ MAF Sensor Cleaning – Fix error code P2282 and boost power

✅ Engine Oil Change – How to do your own oil change

✅ Badge Replacement – Fix a missing or stolen Vauxhall/Opel emblem

Clean the MAF sensor and change the air filter!

Think of your car like yourself — you need to breathe properly to perform at your best. When you have a cold and your nose is blocked, you feel run down, tired and generally not yourself.

Your car can be similar. If the air filter becomes clogged with dust and dirt, or the MAF sensor gets coated with oily residue, it can affect how accurately the engine measures the amount of air entering the engine. This can lead to the engine running less efficiently, resulting in reduced MPG, rough idling and sluggish performance.

The good news is that both of these are relatively simple things to check and maintain, so a little basic maintenance can go a long way. The MAF Sensor clean I use is another liqui moly product which can be found on the product page on Amazon here (Clickable link)

Change your oil every 6 months!

I change my oil every 6 months. For me this typically is March & September this is mainly due to the weather as it's dry and not too cold. My MOT is also at the start of October so I need my old diesel car to pass the emmisions test which are very strict in the UK.

For this I use Shell Helix Ultra Professional AG 5W-30

Shell claims to improve fuel efficiency by 1% which doesn't sound much but that could be 1 miles every 100 miles you drive for free...... Superior Engine Protection, Advanced Engine Cleanliness, Improved Fuel Efficiency!

My Tool Kit

My Teng Tool kit does around 90% of the jobs

This kit I do about 90% of my jobs with on both car and boat!

The Teng Tools T1436 is a 36‑piece 1/4in drive metric socket set built for both DIY and professional use, offering durability and precision through strong chrome vanadium steel construction. The set includes 10 hex sockets (4–13mm), 6 deep sockets (6–13mm), a reversible ratchet, hex adaptor, universal joint, 50mm and 100mm extensions, T‑bar adaptor, slotted, Phillips, Pozidriv, hex and TORX bits, plus three hex keys. Supplied in a tough plastic case with a snap‑lock lid and metal hinges, it keeps every tool organised and ready for workshop, automotive and home use.