Used SUV Buying Guide: What to Check Before You Buy

Start with this one because it's the most expensive to fix and the easiest for a seller to hide. Park the car on a flat surface, engage four-wheel drive, and then select low range if the vehicle has it. Listen for any grinding or clunking as the transfer case engages — a healthy system should shift smoothly and without drama. If the car has a rear diff lock, engage it at low speed and feel for the characteristic binding sensation as you attempt a gentle turn. No binding means the diff lock isn't working. On modern SUVs like the Land Rover Discovery Sport or Toyota RAV4, the 4WD system may be fully electronic — open the driver's door menu or terrain response system and cycle through every mode. Any warning lights that flicker on during this test are a red flag. Ask when the transfer case oil was last changed. Most manufacturers recommend every 40,000–60,000 miles, and very few owners actually do it.

Around 40% of all SUVs sold in the UK are either factory-fitted or aftermarket-fitted with a tow bar. That's not a problem in itself. The problem is when a car has towed beyond its rated capacity or the tow bar has been poorly fitted. Crouch down and inspect the chassis rails where the tow bar bracket bolts to the bodywork. Look for cracking paint, unusual welds, or surface corrosion that doesn't match the rest of the underside. Check the wiring loom — it should be neatly loomed and secured, not taped up and hanging loose. If the tow bar has been removed, look for bolt holes in the chassis. Ask the seller what the car towed, how often, and whether it stayed within the manufacturer's rated towing capacity. A £30,000 SUV used to tow a 2,500kg caravan when it's only rated for 2,000kg is a structural problem you cannot unsee.

Roof rails look like they sit on top of the bodywork, but the bolts go through it. On older or poorly maintained SUVs — especially those that have been used on roof racks or had roof boxes fitted — the fixing points can corrode from the inside out. Run your fingers along the base of each roof rail. Any spongy paint, bubbling, or visible rust here means water ingress has already started. Sunroof drains are a separate issue. Every panoramic or standard sunroof has drainage channels that run down inside the A and C pillars. When they block — and they do, regularly — rainwater overflows into the headlining or footwells. Press the headlining around the sunroof aperture. Any soft spots or staining indicate water has been pooling. Unblocking the drains is cheap; replacing a water-damaged headlining or ECU is not.

The diesel particulate filter (DPF) traps soot particles from the exhaust. It clears itself through regeneration — a process that requires a sustained run at motorway speeds and temperatures. SUVs used mostly in towns or for short commutes rarely complete a full regeneration cycle, so soot accumulates. A partially blocked DPF will trigger a warning light, reduce power, and eventually go into limp mode. A fully blocked DPF typically costs £1,500–£3,000 to replace, depending on the model. At the viewing, check the dashboard for any DPF or engine management lights. Ask the seller whether the car ever flagged a DPF warning and how they cleared it. If they had it 'cleaned' at an independent garage, ask for proof. If the car has a live data port and you have an OBD reader, check the DPF soot load reading — anything above 80% is cause for concern. A car that has done mostly motorway miles is a much safer diesel SUV bet than one with 15,000 miles of urban driving.

The free DVLA MOT history checker shows every test, every failure, and every advisory going back years. For a used SUV, this is one of the most revealing documents available. Look specifically for recurring advisories on the same components — if an advisory for 'nearside rear suspension arm bush deteriorating' appears in three consecutive MOTs, it means the car has been running on degraded bushes for years. The same applies to brake disc wear, steering rack play, and anti-roll bar link wear. SUVs are heavier than the average car and their suspension components wear accordingly. A pattern of deferred maintenance on bushes, dampers, and brake components tells you the car has been run on the minimum rather than properly serviced. Cross-reference the MOT history with the service history — if advisories appear in MOTs but there's no corresponding work in the service records, you know corners were being cut.

Air suspension transforms the driving experience of a premium SUV — the Range Rover Sport, BMW X5, Mercedes GLE, and Audi Q7 all offer it, and it's genuinely excellent when it works. When it fails, it's genuinely expensive. The air compressor that pressurises the system typically lasts 80,000–120,000 miles before it starts to struggle. Air bags can perish and crack, especially on cars that have been parked for long periods or lived in colder parts of the country. Check that the car sits level before you start the engine. An uneven ride height — one corner sitting lower than the others — indicates an air bag leak. Start the car and let it run: the suspension should self-level within 30 seconds. Drive over a speed bump and count how many times the dampers cycle before settling. If the car wallows or takes several oscillations to settle, the dampers are worn. A full air suspension rebuild on a Range Rover can cost £4,000–£8,000. Factor that into your offer, or walk away.

You might be buying a Chelsea tractor that has never seen a muddy field, but you still need to inspect the underside. Urban SUVs are regularly driven over kerbs, up onto pavements, and into poorly maintained car parks. The result is often cracked undertray panels, bent bash plates, and damaged brake lines that the owner doesn't even know about. If you can, use a torch and inspect the full underside — you're looking for fresh scuffs in the underbody coating (a sign of recent ground contact), bent or cracked undertray sections, corrosion on the exhaust heat shields, and any fluid leaks from the gearbox, transfer case, or differentials. On genuine off-road vehicles like a Jeep Wrangler, Toyota Land Cruiser, or older Defender, look for dents in the axle casings, missing or bent diff guards, and stone damage to the oil sump. A car that has genuinely been used off-road isn't automatically a bad buy, but you need to know what you're getting.

Most modern SUVs offer at least two or three drive modes — typically Eco, Normal, and Sport, with terrain-specific modes like Sand, Mud, or Snow on more capable vehicles. At the viewing, activate every one of them. Each mode should produce a perceptible change in throttle response, steering weight, or suspension firmness. If switching modes produces no change at all, suspect a fault in the drive mode selector or associated electronics. Stability control and hill descent control are equally important. Find a steep enough incline, engage hill descent control, and take your feet off the pedals — the car should hold a slow, controlled descent under braking without any input from you. Test the lane-keeping assist, emergency braking, and adaptive cruise control if fitted. These systems are expensive to repair and increasingly important for MOT purposes. A quick test on the road takes five minutes. A repair bill for a faulty stability control module takes five weeks and costs significantly more.