The car that re-established Audi's performance pedigree and spooked the M3 is just as accomplished second-hand.
You’ll pay 50 per cent more for fuel today than when we road tested the Audi RS4 back in March 2006, yet it is one big-engined saloon that hasn’t suffered a catastrophic dive in value for it. We struggled to find fault with the car’s abilities back then, which is a sentiment that’s withstood the power of hindsight, and has transferred to the mainstream, keeping prices strong.
Even ignoring fuel costs, the RS4 can be an expensive car to own. While the roaring V8 and deeply impressive hydraulic dynamic ride control (DRC) system are the two main reasons why this car can play both hot rod and cruiser, they aren’t without foibles that betray Audi’s Teflon image. Early examples suffered rough running and the occasional misfire from cold, soon tackled by a new ECU and different spark plugs, but the problem of carbon fouling in the engine endures.
Not uncommon in FSI engines, due to their high valve-overlap action, you’ll often find black deposits on the inlet tracts, which cause a loss in power. Gift your RS4’s V8 with regular trips towards the red line and it should stay tolerable, but less exercised engines can suffer from heavy crusting that’ll cost £600 or so to clean up.
Flaps in the intake manifold and exhaust can seize, the former sending the engine into safe mode, the latter dulling the exhaust note, which is especially noticeable in Sport setting. A diagnostic check reports both.
The DRC system was first seen in the RS6, and tended to leak from the dampers, incurring a complicated chain of replacement parts to fix. Though much improved, the RS4 suffers the same symptom, and despite a more modular setup, changing two front dampers will still cost around £800 all in.
Another significant burden can be the brakes, but despite adding a premium of £500-£1000, the rare carbon-ceramic option not only negates the steel alternative’s fading problem but is likely to cost you less in the long run thanks to far superior durability.
Also factor in £350 or £600 for a minor or major service respectively, bearing in mind an oil change is recommended by Audi specialists like Fontain Motors in Bucks every 5k-10k miles.
Yet, despite high running costs, the RS4 still proves a hit in the used market. Fontain boss Marcus Robinson attributes this largely to buyers who’ve “given up sports cars in favour of something more family-friendly that offers both safety and performance”; a claim backed up by the number of Boxsters and the like he’s taken in trade for RS4s.
After a tough couple of years, he says “prices are definitely firming up”, and recommends low-mileage examples as the best investments. In terms of spec, the sporty bucket seats work best in the saloon, while more practically minded Avant estate buyers look for the harder wearing, more comfortable and less bulky ‘comfort’ choice. Sat nav is also a sought-after option, while it’s best to avoid the clunky bolt-on phone cradle in favour of standalone Bluetooth.
What to look out for:
Loafing, knocking suspension under load is a sign of DRC leakage. Check for fluid on the dampers.
Intake manifold flaps that are faulty or have a worn motor will be flagged with an engine warning light and reduced performance. Not a cheap fix.
Carbon-ceramic discs should outlast steel at least fourfold, but check closely for cracks.
Re-enable the tyre pressure sensors if they’ve been switched off. Expired sensors cost around £80 each and could be a bargaining tool.
Sluggish power delivery could signify carbon fouling, but a little
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