Audi Q5 (8R) common problems: what to check before you buy

The first-generation Audi Q5 (the 8R, built from the late 2000s until it was replaced later in the 2010s, with a facelift partway through) is a solidly made, comfortable family SUV that most owners get on with well — but it has a short list of genuinely characteristic weak points, and which ones apply to you depends almost entirely on the engine under the bonnet. The headline items are oil consumption and timing chain tensioner wear on the earlier 2.0 TFSI petrol, sooted EGR systems and blocked diesel particulate filters on the diesels, low-speed manners on the seven-speed S tronic, front suspension bushes, and water finding its way into the cabin through blocked roof and scuttle drains. None of that makes the Q5 a bad car — it makes it a car worth inspecting properly. This guide is a list of things to check, not a verdict.

Which engine you're looking at matters more than the year

Almost every Q5 problem list you'll read is really an engine problem list, so start by identifying exactly what you're buying. On the petrol side the 8R was offered with a turbocharged 2.0 TFSI four-cylinder, a naturally aspirated 3.2 FSI V6 on earlier cars, and — in some markets, notably North America — a supercharged 3.0 TFSI V6. On the diesel side it's a 2.0 TDI four and a 3.0 TDI V6, plus the twin-turbo 3.0 BiTDI in the European SQ5. Exactly which of these was sold varies by market, so check the car in front of you rather than the brochure you read online. All Q5 diesels are common-rail; the older PD (pumpe düse) unit injector engines were gone before this model arrived, so anyone describing a Q5 as a PD diesel has it wrong.

Timing drive is the other fork in the road. The 2.0 TDI runs a rubber timing belt with a defined replacement interval — treat missing belt evidence as a cost, because a belt failure on this type of engine is usually terminal. The 2.0 TFSI, the petrol V6s and the 3.0 TDI V6 all run chains, and on these longitudinal Audi engines the chain drive sits at the flywheel end of the engine. That matters: chain work is not a quick front-of-engine job, and the labour involved is what makes it expensive rather than the parts.

• Petrol: 2.0 TFSI is turbocharged (not supercharged); the 3.2 FSI V6 is naturally aspirated; the 3.0 TFSI V6, where it was sold, is supercharged.
• Diesel: 2.0 TDI belt-driven, 3.0 TDI V6 chain-driven — very different maintenance pictures.
• Quattro on the Q5 uses a mechanical centre differential, not the Haldex clutch found in transverse VW Group cars, so there is no Haldex oil service to chase here. Some later 2.0 TDIs were front-wheel drive in certain markets.

Petrol engines: oil consumption, chain tensioners and carbon

The 2.0 TFSI in earlier Q5s is well known for using oil — enough that owners carry a bottle and top up between services. It stems from the oil control arrangement in the pistons and rings, and the proper fix is internal engine work rather than a cheap bolt-on. Revised pistons and rings exist as a repair. A car that has been topped up sensibly and has full history is not automatically a problem; a car whose level is at the bottom of the dipstick, or that has visible blue smoke on a cold start or on the overrun, needs investigating before money changes hands.

The other 2.0 TFSI item is the timing chain tensioner. The classic symptom is a brief rattle from the back of the engine in the first second or two after a cold start, or a rattle as the engine shuts down. A revised tensioner was released, and many cars have had it. Take a chain rattle seriously: if the chain jumps, valves and pistons can meet, and the repair goes from a tensioner to an engine. If you hear it, stop and get it diagnosed rather than driving on and hoping.

The naturally aspirated 3.2 FSI V6 has its own reputation for chain and tensioner wear at the flywheel end — again heard as a start-up rattle — and because the job typically means removing the engine or the gearbox to reach the chains, it is one of the biggest single bills on an 8R. All of these direct-injection petrols also build carbon on the back of the intake valves over time, which shows as a lumpy cold idle, misfire codes and a general lack of sparkle; the remedy is manual or media cleaning of the ports.

• Check the oil level yourself on a level surface before the test drive, and ask how often it needs topping up.
• Listen with the bonnet up on a genuinely cold start — a warm engine hides chain noise.
• Plastic thermostat and water pump housings on the 2.0 TFSI are a known leak point: look for crusty coolant traces and a low expansion tank.
• A failed crankcase breather (PCV) diaphragm on the 2.0 TFSI gives rough idle, a whistling or sucking noise and lean-running codes.

Diesel engines: EGR, DPF and intake flaps

Both Q5 diesels are strong, torquey engines that suit the car, and both dislike a life of short cold journeys. The exhaust gas recirculation valve and cooler soot up, which brings on the engine light, rough running and sometimes a noticeable loss of power. The diesel particulate filter needs regular long runs to regenerate properly; a car used only for school runs will eventually block one, and a filter whose regenerations are repeatedly interrupted can also lead to fuel diluting the engine oil. Ask the seller what the car actually does each week — that tells you more than the mileage does.

The intake manifold flap actuator is a very familiar VW Group diesel fault and turns up on the Q5 too, usually as a stored flap position code and sometimes a limp mode. On the 3.0 TDI V6, oil cooler and thermostat housing leaks are worth looking for, along with the same EGR and DPF themes. Piezo injectors can weep at their seals, which shows as a sooty deposit around the injector and a diesel smell or a soft chuffing noise at idle. Glow plug failures show up in cold weather as a stumbling start and a warning light.

Some 2.0 TDI cars of this era were covered by an emissions-related service action, though whether a particular car is affected depends on its exact engine and the market it was sold in — so ask to see the paperwork rather than assuming either way. Later diesels in some markets use AdBlue; if the car has it, make sure the system is filled, functioning and free of stored faults, because these systems can prevent the car restarting once they have counted down.

• Look for a DPF that has been physically removed or software-deleted — it is an MOT and legality problem in the UK regardless of how it drives.
• Black soot around the tailpipe on a modern diesel is normal in small amounts; heavy smoke under acceleration is not.
• Check the oil level is not above maximum — a rising level on a diesel points at fuel dilution from failed regenerations.

Gearboxes and drivetrain

Depending on year, engine and market you will find a six-speed manual, the seven-speed S tronic dual-clutch, or a conventional torque-converter automatic — typically six speeds on earlier cars and eight on later ones, though the split differs between markets, so confirm what the car actually has. The S tronic used here is a wet-clutch design, and its fluid and filter service is the single most important thing in its history file. Symptoms to watch for are hesitation or a shunt when pulling away, a shudder as the clutches take up, jerky changes in stop-start traffic, or the car refusing to select a gear. Some low-speed clumsiness is normal for a dual-clutch; a distinct shudder or a flare between gears is not.

The torque-converter automatics are generally the easier-going choice and rarely cause drama, but fluid changes are still worth doing regardless of any 'lifetime fill' claim. On manuals, listen for dual-mass flywheel rattle at idle with the clutch up, and feel for a high or vague biting point. On any car, check the propshaft and driveshaft boots for splits and grease, and listen for droning or vibration that changes with speed rather than with engine revs.

• Ask for dated evidence of a gearbox oil and filter service on an S tronic car — a stamp that says 'service' is not enough.
• Test low-speed manoeuvring properly: a three-point turn and a hill start reveal dual-clutch problems that a motorway run will hide.
• A gearbox warning light or a car that drops to neutral needs diagnosis before purchase, not afterwards.

Suspension, steering and brakes

The Q5 uses a multi-link front suspension with a lot of aluminium arms, and the bushes and ball joints in it are a wear item rather than a fault. Worn ones give a knock or clonk over broken surfaces and speed bumps, steering that feels vague or wanders on the motorway, and uneven tyre wear — often on the inner shoulders. Anti-roll bar drop links make a lighter, tinnier rattle over small bumps and are one of the cheaper jobs on the car. It's a heavy car on large wheels, so tyres and brakes wear at a rate that surprises people coming from a saloon.

The electromechanical parking brake has small motors on the rear calipers. Faults here show as a parking brake that won't release, an amber warning, or a message asking you to service the system. It also means rear brake work needs a diagnostic tool to wind the calipers back into service position — trying to force them is how people damage them. Anything to do with ABS, ESP or the steering deserves a conservative approach: if a warning light is on for those systems, treat the car as needing diagnosis before it is driven hard or bought.

• On the test drive, find a rough road and a speed bump and listen with the radio off.
• Check tyre inner edges by feel as well as by eye — feathering there usually means geometry or worn arms.
• Apply and release the electric parking brake several times, including on a slope, and check it holds and releases cleanly.

Water ingress and electrics

This is the fault that catches people out, because the symptoms often look electrical rather than watery. The drains for the sunroof or panoramic roof and the drains in the scuttle at the base of the windscreen can silt up with leaf debris, and once they do, water backs up and finds its way down into the cabin. The first signs are a musty smell, windows that mist up persistently, damp underlay in a footwell, or condensation in a light unit. Left alone, water reaches connectors and control units low in the car, and then you get strange, apparently unrelated electrical behaviour: modules dropping off the network, warning lights that come and go, or a battery that flattens itself over a few days.

Check the boot too. Lift the boot floor and press the carpet in the spare wheel well, look at the tailgate seals and light clusters, and operate the tailgate — the wiring loom passing into a tailgate flexes every time it is opened, and broken cores in there cause wipers, lights or locking to misbehave intermittently. Batteries themselves are worth a thought: on cars with start-stop, a replacement battery should be registered to the car electronically, otherwise the charging strategy never quite matches the new battery and it leads a short life.

• Trickle a little water into the sunroof channels and check it drains away under the car rather than appearing in a footwell.
• Feel all four footwells with the flat of your hand, not just a glance.
• An intermittent electrical gremlin on an 8R is a leak until proven otherwise.

Interior, trim and equipment

A few known irritations are worth looking for. The soft-touch coating on switchgear and MMI controls can go sticky or start to peel with age and cleaning products, which looks worse than it is but is hard to reverse. MMI systems of this vintage can be slow, and drive or media errors do appear. Seat heater elements fail, usually on the base of the driver's seat. Panoramic roofs and boot trim generate their share of rattles, and roof blinds can jam.

Use every switch, every seat adjustment, both heaters, the roof, the tailgate and the air conditioning during a viewing — this is the cheap part of the inspection and it is the part people skip. Electrically operated tailgates in particular should run smoothly in both directions and hold themselves up when stopped.

• Cycle the climate control from cold to hot and check both sides blow at the right temperature.
• Try every seat and mirror memory position and both heated seats to temperature.
• Open and close the roof and its blind fully, listening for grinding.

What to check on a test drive or pre-purchase inspection

Insist on a properly cold start. Almost every important Q5 fault — chain rattle, diesel smoke, glow plug problems, a lumpy carbon-fouled idle — is at its most obvious in the first few seconds of running and invisible on a car the seller has already warmed up for you. If you arrive and the engine is warm, come back another day.

After that, work through the car deliberately. Check the oil level and the service history together. Drive at low speed in traffic, then on a fast road, then manoeuvre on full lock. Watch that every warning lamp illuminates at ignition-on and then goes out, because a bulb removed from the cluster hides a fault. Finish with a diagnostic scan of every module rather than the engine alone — a basic OBD reader only sees emissions-related engine faults, and the Q5 carries dozens of control units.

• Cold start with the bonnet open; listen at the bulkhead end of the engine.
• Oil level, oil condition, and whether the level is above maximum on a diesel.
• Belt evidence on a 2.0 TDI; any chain rattle on the petrols and the 3.0 TDI.
• Low-speed dual-clutch behaviour, hill start, full-lock creep.
• All four footwells and the spare wheel well for damp.
• Every warning light comes on, then goes out. No lamps missing.
• Electric parking brake applies and releases; brakes pull up straight.
• Tyre wear pattern across the tread, especially inner edges.
• A full all-module scan, with stored and pending faults read before and after the drive.

Fault codes that commonly turn up — and what they usually mean

A stored code tells you which circuit or function the car is unhappy about. It does not tell you which component has failed. Codes are the starting point of a diagnosis, not the answer, and on this car more than most it pays to look at live data before buying anything — a lean code can be a split hose, a breather diaphragm or a failing sensor, and only measured values separate them. The Q5 also stores VAG-format five-digit codes alongside the standard P-codes depending on the module, so read both.

Codes seen often on the 8R include camshaft and crankshaft correlation faults, which on the chain-driven petrols are worth taking seriously — they can point to chain stretch, a tired tensioner or a cam adjuster, not just a sensor; lean running codes on the 2.0 TFSI, which frequently trace to the crankcase breather or a boost leak; underboost codes, which point at boost leaks, wastegate or vane actuators or the turbo itself; intake manifold flap position codes on diesels, usually the flap actuator motor; EGR flow codes from a sooted valve or cooler; particulate filter efficiency and soot accumulation codes from failed regenerations or a genuinely blocked filter; fuel rail pressure codes on diesels, which can be a filter, a high-pressure pump or leaking injectors; engine temperature codes from a stuck-open thermostat; and communication or module-not-responding codes, which on this car should always make you think about water and wiring first.

Reading all of that properly needs a tool that talks to every control unit in the car rather than only the engine. VAGPULSE — the Windows software and cable sold on this site — scans every module on a VW, Audi, Skoda or SEAT, shows live measuring values while the engine runs, and handles coding and adaptations such as registering a new battery or putting the electric parking brake into service position. For a pre-purchase check on an 8R, the value is in seeing the whole car at once.

Common questions