Some cars look cheap because they have depreciated heavily. The problem is the repair costs haven't depreciated with them.
Some cars look cheap because they have depreciated heavily. The problem is the repair costs haven't depreciated with them.
These are 10 cars I'd check very carefully before buying, what normally goes wrong, and what I'd physically look for.
Range Rover Sport / Discovery — 3.0 TDV6 & SDV6
Main issue: crankshaft and main bearing failure. Once this starts, it can quickly turn into complete engine failure.
What I'd check:
- Engine must be completely cold
- Listen for deep knocking or rumbling from the bottom end
- Check oil pressure faults
- Check oil condition and service history — frequent oil changes are a big positive
- Avoid cars that have regularly gone to maximum service intervals
- Check DPF condition, because excessive regeneration can affect oil condition
- Check for metal contamination in the oil/filter if possible
Insider tip: a quiet engine does not guarantee the crankshaft is healthy. The best protection is buying one with excellent maintenance history and frequent oil changes.
Would I buy one? Yes, but only with very good history and a proper inspection.
Discovery Sport / Evoque / F-Pace — 2.0 Ingenium Diesel
Main issues: timing chain wear, DPF problems, oil dilution, turbo problems and EGR faults. These problems can all be connected — during DPF regeneration, additional fuel is injected to increase exhaust temperature, and repeated or failed regenerations can allow diesel into the engine oil. This dilutes the oil and reduces lubrication quality, which then increases wear on components such as the timing chain and turbo.
What I'd check:
- Cold-start timing chain noise
- Engine oil level — above maximum can indicate fuel dilution
- DPF differential pressure and calculated soot load
- Regeneration history and distance since last regeneration
- EGR faults and exhaust temperature sensor faults
- Service interval history
Insider tip: I would rather buy an Ingenium diesel that has done 80,000 motorway miles than one that has done 40,000 miles of short journeys. Low mileage does not automatically mean low wear on a modern diesel.
Would I buy one? Only with strong service history and good DPF data.
BMW 320d / 520d — N47 Diesel
Main issue: timing chain wear. The timing chain is mounted at the rear of the engine, making replacement much more involved than on many engines.
What I'd check:
- Cold-start chain noise
- Metallic scraping or rattling from the rear of the engine
- Proof of timing chain replacement
- Exact engine code
- Oil change intervals
- DPF condition
- Injector correction values
Insider tip: never accept that a timing chain has been replaced without an invoice. You want to know who fitted it, what parts were used, what was actually replaced, and at what mileage.
Would I buy one? Later engines with strong history can still be very good cars. Early N47s with poor history need much more caution.
Audi A6 / A7 — 3.0 TDI
The 3.0 TDI is actually a strong engine when maintained properly. The problem is the amount of expensive equipment around it.
Common issues: intake manifold swirl flap faults, EGR problems, DPF problems, timing chain noise on some engines, coolant leaks, and gearbox problems if servicing has been ignored.
What I'd check:
- Full diagnostic scan
- Swirl flap position faults
- DPF soot load and differential pressure
- Cold-start chain noise
- Gearbox service history and engagement from cold
- Coolant leaks and oil leaks underneath the engine
Insider tip: always find out the exact engine code. Different versions of the 3.0 TDI have different common problems.
Would I buy one? Yes. A properly maintained 100,000-mile 3.0 TDI wouldn't bother me.
Mercedes E220 / E250 CDI — OM651
These engines can cover very high mileage, but maintenance matters.
Common issues: injector problems on earlier engines, timing chain/tensioner wear, DPF faults, EGR faults, and cooling system leaks.
What I'd check:
- Cold-start timing chain noise
- Injector correction values and injector sealing
- DPF differential pressure and regeneration history
- Coolant level
- Service history
Insider tip: look around the injectors for black carbon build-up. This can indicate combustion gases leaking past the injector seal — catching this early can save a much bigger repair later.
Would I buy one? Yes. A properly maintained OM651 can do serious mileage.
Ford Ranger / Transit / Transit Custom — 2.0 EcoBlue
Main issue: wet timing belt. The timing belt runs inside the engine oil, so oil condition and correct oil specification are extremely important. If the belt begins breaking down, belt material can contaminate the oil, which can restrict the oil pickup and cause low oil pressure — at that point the problem can become much bigger than just replacing a timing belt.
What I'd check:
- Timing belt history
- Correct engine oil specification and oil change intervals
- Oil pressure faults
- Oil pickup contamination if belt deterioration is suspected
- DPF condition and oil dilution
- Turbo condition
Insider tip: if buying one with questionable belt history, price a complete wet-belt job into the purchase. If deterioration is found, don't just replace the belt — the oil system needs checking for contamination as well.
Would I buy one? Yes, but belt history is one of the first things I'd want to know.
VW Transporter 2.0 BiTDI 180 — CFCA
This is one I would be particularly careful with.
Main issue: excessive oil consumption and cylinder bore wear. The EGR cooler has also been linked with engine wear issues on these engines. Once the cylinder bores are damaged, replacing an external component will not repair the engine.
What I'd check:
- Exact engine code
- Oil consumption, compression and exhaust smoke
- DPF condition
- Engine oil analysis if spending serious money
- Previous engine work and EGR cooler history
Insider tip: ask how much oil the engine actually uses. Don't just rely on the dashboard level or whether it currently looks full — oil consumption history can tell you a lot about these engines.
Would I buy one? Only after a very thorough inspection. One of the higher-risk engines on this list.
Porsche Cayenne — 3.0 Diesel
The engine itself can be very good. The expensive part is everything else attached to it.
Areas to check:
- Transfer case and gearbox
- Air suspension if fitted
- Coolant leaks and oil leaks
- DPF and EGR
- Intake system
- Suspension arms and electronic faults
What I'd do: run a full vehicle scan — not just the engine ECU. Check the engine, gearbox, transfer case, suspension, parking brake and body control systems, then get it on a ramp and look properly around the undertrays.
Insider tip: undertrays can hide serious oil and coolant leaks. A dry garage floor does not mean the car has no leaks.
Would I buy one? Yes, but I would keep money aside for repairs. Cheap purchase price does not mean cheap Porsche ownership.
Volkswagen Golf R Mk7
The biggest risk with these isn't always the engine. It's previous owners.
Things to check:
- Previous ECU tuning, downpipe changes and intake modifications
- Haldex servicing and DSG servicing
- Water pump/thermostat housing leaks
- Misfire history and boost faults
- Tyre condition
Haldex: the rear differential system relies on a hydraulic pump. Contamination around the pump gauze can cause problems and reduce rear-wheel-drive engagement — check the Haldex ECU for faults and confirm the system is actually operating.
Cooling system: water pump and thermostat housing leaks are common. Look for low coolant, pink/white dried coolant residue, coolant smell, and previous replacement history.
Insider tip: look for signs a modified car has been returned to standard. Fresh bolts, disturbed clamps, non-original clips and marks around the downpipe or intake can tell you more than the advert.
Would I buy one? Definitely. But I'd rather buy a completely honest modified car with good maintenance than a badly abused car pretending to be standard.
Mercedes-AMG A45 — W176
The M133 engine is very impressive but it's a highly stressed 2.0 turbo engine. How the car has been driven matters.
Things to check:
- Service intervals and oil level
- Misfire counters and boost faults
- Turbo condition and gearbox operation
- Differential noise and engine mounts
- Brake condition and tyres
- Previous tuning
What I'd pay attention to: the gearbox should engage correctly and shift cleanly. Check all four tyres carefully — different brands, incorrect sizes or badly uneven tread can cause problems on four-wheel-drive cars and normally tells you something about how the vehicle has been maintained.
Insider tip: don't automatically avoid a modified performance car. A properly maintained car with documented modifications can be safer than one that has been modified, abused and then returned to standard before sale.
Would I buy one? Yes. But it needs inspecting like a performance car, not like a normal A-Class.
One Of The Biggest Mistakes: Buying On Mileage
Mileage is only one part of the picture. For modern diesels especially, usage matters. A hundred miles at motorway speed is completely different to twenty separate five-mile journeys.
Short journeys can cause failed DPF regeneration, increased soot loading, oil dilution, EGR contamination and intake carbon build-up. This is why I don't automatically choose the lowest-mileage car.
Full Service History Doesn't Mean Perfect
Always check what the service history actually contains. A stamped book doesn't tell you what oil was used, whether the gearbox or Haldex was serviced, whether DPF problems have been ignored, whether an engine is consuming oil, whether the vehicle has previously been tuned, or whether faults have simply been deleted before sale.
Invoices are much more useful. They show what has actually been done.
The Diagnostic Checks I Like To See Before Buying
On a modern diesel:
- DPF differential pressure and calculated soot load
- Ash loading where available
- Regeneration history and distance since last regeneration
- Exhaust gas temperatures
- Injector correction values
- EGR requested vs actual position
- Boost requested vs actual pressure
- Stored and historic fault codes
On a performance petrol:
- Misfire counters
- Boost pressure and fuel trims
- Knock correction where available
- Cooling system condition
- Gearbox faults
- Four-wheel-drive system faults
A diagnostic scan is much more than checking whether the engine-management light is on.
Final Advice
Before buying one of these cars, check:
- Cold start
- Service invoices
- Exact engine code
- Live diagnostic data
- DPF condition
- Gearbox history
- Oil and coolant leaks
- Previous modifications
- Tyres and brakes
- The underside of the vehicle
Most expensive failures leave clues. The key is finding them before you own the car.
Alfie has over 11 years of experience in the motor trade and founded Alfa Prestige to give buyers the insider knowledge that was previously only available to professionals.
