Looking for help with an old V6 TDI leaking oil


New member
Aug 11, 2023
Prague, Czech Republic
2.5 TDI V6 BDG 163hp
Dear TDI drivers,

I am looking for some advices how to deal with this issue that started to become hopeless after troubleshooting for months.

The car is Skoda Superb 2.5 TDI V6, engine code BDG, transmission FAD (ZF 5HP19). Total of 360 000 km, original turbo and injectors.

Background of the issue:

-Car was leaking oil from the rocker covers, dripping on the exhaust and smelling like burnt plastic. Got the injector seals done and the cover seals replaced. The leak seemed to have disappeared for a while. Oil cooler gasket was changed.

-Initially suspected the infamous 5HP19 bushing, due to the original oil puddle on ground, which was controlled and not in cause apparently.

-After few weeks, small drop like leaks started to appear on the injector sealant that was applied. I used this opportunity to replace the injectors that were original. Bought Euro 3 injector bodies (that have the reputation to remain in good condition) and replaced the tips. Wobble at idle disappeared, but it didn't have the improvement I was hoping for. Fuel burn remained 20 to 30% higher than used to (seems to be a computer issue though).

-Did an oil change, oil and air filter. Car started to progressively have a bigger oil puddle every day under the engine.

-Observed abnormal MAF values and boost lag (see attachment) in VCDS during full load accelerations. Intake was full of carbon and oil. Decided to entirely clean the manifold and ports. Managed to achieve the necessary results and most of the carbon was removed. EGR was blanked. The PCV membrane was changed. It was tired, but not torn apart. Crankcase ventilation system was reasonable gummed up and cleaned.

-MAF and boost remained the same, no changes in the car behavior. Oil puddle still present after every start.

-Intake manifold remains full of oil after every usage of the car. Oil seems to pool from the compressor output to the intercoolers. There are no boost leak, vacuum leak or other hoses that have some abnormalities. Turbo makes siren / whistle when reaching 2000-2200 rpm on spool up. Always did it for 10 years and 200 000 km driven since then.

-Blow by and PCV are checked. Blow by is low, the oil cap doesn't dance at all (would maybe even think as a slight vacuum). At high speed on highway, the car uses on average 1 liter of oil every 500 km, up to 1 liter for 300 km at very high speed. The whole car is covered in oil, impossible to say if burnt or splashed.

-The oil level on the dipstick takes about 24h to come back to its level, making it very difficult to estimate the precise oil consumption.

Car has some slight lack of power, but performs well, and fuel consumption seems to be in check more or less. City driving and idling seem to have a very big toll on the fuel burn, but all together, I wouldn't be concerned so much about it.

I can add turbo pictures, various videos if necessary, but I am running out of ideas. Should I suspect piston rings, valves...? What could cause such a massive oil leak externally, and also internally? It is almost impossible to locate the origin of that external leak. Would the turbo be leaking that much oil, that it would escape through the hoses dripping down?

Thanks in advance for any help with this unsolvable issue!