By 70–100,000 km the 3.0T's six Bosch injectors leak down and their seals weep fuel into the oil. We replace the complete set with new seals at your home, in one visit.
The Bosch direct injectors in the supercharged B8-era 3.0T live a hard life — seated in the combustion chamber, cycling at high pressure, exposed to full combustion heat. By 70–100,000 km they leak down: the internal sealing surfaces wear until injectors dribble after they should have closed, and their spray patterns degrade from a precise cone to an uneven spit. Cylinders stop receiving matched fuel charges, and the engine tells you with P0300-series misfire codes and a rough idle.
The second failure is sneakier: the injector seals weep fuel past them into the crankcase, diluting the engine oil. Fuel-thinned oil loses film strength — and that's the oil protecting your bearings, cam lobes and turbocharger journals. You can catch it on the dipstick: a level mysteriously rising, or oil that smells distinctly of gasoline. Oil dilution is a quiet engine-killer because nothing about it feels wrong from the driver's seat.
On a six-injector engine at this age, replacing the failing one or two is false economy: the others share the same hours and the same wear, and access on this supercharged V6 is the bulk of the labour. The proper repair is the complete set — six new injectors, all new seals — bringing every cylinder back to a matched baseline and stopping the dilution at its source.
If your Audi is doing any of these, this is the likely cause:
Two damage paths run in parallel. Misfires dump unburned fuel into the catalytic converters, which overheats and ruins them — cats for this car are an expensive add-on to what should be an injector job. Meanwhile fuel dilution is thinning the oil protecting every bearing in the engine, and bearing wear is cumulative and irreversible. Neither path announces itself loudly; both are well underway by the time the misfires are constant.
Yes — it's a day of careful top-of-engine work at your driveway: disassembly for access, six injectors seated with new seals at correct torque, a leak check, and a fresh oil change before the road test. Everything needed comes with us.
Six precision direct-injection units are genuinely expensive parts, and the access labour on the supercharged V6 adds most of a day at dealer rates — hence $2,500–3,500. We quote one flat price for the complete set, seals, oil change and testing before any work starts.
Mechanically yes, economically no. The access labour is identical for one injector or six, and the remaining five have the same mileage and the same wear curve — replace one now and you're paying the teardown again within the year. One matched set, one labour bill, done.
Worn injector seals let fuel weep past into the crankcase, where it thins the oil. Thinned oil can't maintain the protective film your bearings and turbo journals depend on — it's engine wear happening silently. New seals stop the leak, and the included oil change clears out what's already diluted.
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