VW Lupo
The 1.7 SDI AKU is a robust naturally aspirated diesel without turbocharging in the Lupo. Mechanically very long-lived. Typical weak points are age-related injection pump issues (Bosch VP37), a coking EGR system, and power loss from blocked filters. Biodiesel must be strictly avoided.
SDI — All Suck, No Fun
60 hp naturally aspirated diesel in the Lupo — the SDI without a turbo is even more sluggish than the numbers suggest. Only for absolute economy drivers with plenty of patience.
Engine Weaknesses 5
The Bosch VP37 distributor injection pump tends to leak at the pump seals, especially after biodiesel use or at high vehicle age. Leaking pumps must be replaced.
Symptoms: Fuel smell in engine bay, diesel stains under the vehicle, starting problems with a warm engine, engine not reaching full revs
The AKU SDI distributor injection pump leaks at the governor shaft seal or the high-pressure section transition. Fuel drips every second with the engine running.
Symptoms: Fuel smell in engine bay, visible diesel drops under the engine, starting difficulties
The EGR valve on the AKU engine tends to coke up and stick at high mileage. After replacement the new valve must be coded via a diagnostic tool, otherwise the fault returns immediately.
Symptoms: Engine warning light, hesitation under partial load, power loss especially below 1,300 rpm, black exhaust smoke
The SDI engine is very sensitive to a blocked air or fuel filter. Poor filter quality or overextended service intervals lead to severely reduced power — often misdiagnosed as a serious engine fault.
Symptoms: Engine barely pulls, no difference between half and full throttle, top speed drops to 120–130 km/h
On the AKU 1.0 MPI the valve cover also serves as the camshaft bearing cap. The sealing surface is not separate from the bearing area — incorrect sealant leads to oil loss and bearing problems.
Symptoms: Oil patches under vehicle, oil burning on exhaust manifold, oil loss