When should I replace my car instead of repairing it?

Your car is a consumable. One that should last many years but one that does have a use-by date. So when are you better off replacing it rather than repairing it? There's no magic number or situation for every car and buyer. Some cars become uneconomical to repair many years or kilometres before others. Different buyers have different expectations, budgets and priorities.

By the same measure, there are some warning signs that the car's best days are behind it and keeping it running could be more trouble than it's worth. Here are some to look out for.

If you want to know whether your car still makes financial sense, you need to keep a tally of your annual fuel and servicing costs, while keeping track of its resale value. This will allow you to calculate exactly what you're paying to run your car and identify the sometimes subtle point when it no longer tallies with your budget or goals. For example, you'll be able to figure out if a big repair is justified by the value of your car or whether what you're paying each year to keep your current car running exceeds what you could pay to fund and/or run, and service a better or more economical set of wheels.

Some classic-car enthusiasts deliberately curate or preserve a rusty patina (a surface coating on metal that appears red or orange) but that's all about having a harmless dusting of it on non-structural exterior panels. If you only have tiny rust patches, it’s possible to fix them yourself, however if you find rust around your sills, floor, suspension mounts or other key underbody areas, your car's structure and your safety are likely to be significantly compromised. And with serious rust, one of the costliest issues to deal with in the motoring world, you're probably better off putting your money elsewhere.

Your car has all kinds of fluids circulating around it and they're designed to stay in place. If you notice a couple of tiny spots on your driveway or a certain fluid depleted during your periodic under bonnet checks, it might just be something relatively simple and cheap like a failed hose or gasket. But if your driveway is getting comprehensively splattered or multiple fluids seem to be depleting at once, you're likely looking at a series of issues in multiple systems and potentially significant repairs.

Whatever you drive, you don't want to see blue or white smoke coming out the exhaust as it's a pointer to serious engine problems. Black smoke from a newer diesel fitted with a diesel particulate filter (DPF) is also a worry as it means the DPF isn't filtering and a costly DPF replacement could be required. But not all black smoke is an indication of imminent and expensive failure. Old diesels pump it out by design and the same goes for a petrol car, it's more a symptom of tuning issues than serious engine woes.

An automatic gearbox should shift smoothly and decisively. If it hesitates noticeably, clunks while shifting or refuses to engage a certain gear, a costly rebuild could be on the cards.

Not every weird sound is a death sentence. Worn suspension bushes or worn brake pads, for example, can result in loud rattles or a piercing grinding sound respectively but neither is massively costly to address. If you're hearing strange knocks, graunches or rattles from the drivetrain, however, you're potentially looking at costly engine or transmission trouble. Learn more about what sounds your engine is making.

A car in tip-top condition shouldn't really have any smell that stands out. If you notice a burning, toasty or any seriously pungent odour, you could be looking at anything from electrical and engine to transmission or clutch issues.

^Disclaimer

^{Viva Energy Australia Pty Ltd (“Viva Energy”) has compiled the above article for your general information and to use as a general reference. Whilst all reasonable care has been taken by Viva Energy in compiling this article, Viva Energy does not warrant or represent that the information in the article is free from errors or omissions or is suitable for your intended use.}