Why it's a good car
The 1.9-litre ALH turbodiesel is genuinely one of the great engines of the last few decades — owners routinely post 400,000-mile and 500,000-km milestones as a matter of course. It returns exceptional real-world fuel economy, parts are still cheap and plentiful, and underneath the retro body it is a Mk4 Volkswagen sharing its bones with the Golf and Jetta of the same era. That makes it one of the most documented, supported, and DIY-friendly platforms in existence. The engine wants to live forever; the job is making sure the car around it has been kept up.
Does it have a timing belt or a timing chain?
A timing belt — and this matters more than almost anything else on the car. The ALH is an interference engine, which means if the belt lets go the valves meet the pistons and the head is destroyed. It is a scheduled replacement job, and the commonly cited interval for the belt, water pump, and tensioner as a package is around 100,000 miles (about 160,000 km) — with many owners replacing it sooner given it is an interference engine. If the seller cannot show paperwork proving it was done recently, treat the car as needing the full belt service immediately and price that in.
The things to check before you buy
- Timing belt service records Ask, out loud and first, when the timing belt, water pump, and tensioner were last replaced — and demand a receipt. No proof means budget to do the whole job before the car gets driven hard.
- Body and floor pans Get under it with a flashlight. Mk4s rust at the rockers behind the front wheels, the front of the rear wheel arches, the floor pans, and the spare-tyre well. This, not the engine, is what usually ends one of these cars.
- Cold-start smoke A little white smoke for ten seconds that clears is normal. Persistent white smoke once warm points to a head gasket; persistent blue points to worn turbo seals.
- Window regulators A known Mk4 weak point — the plastic clips inside the door fail with age. Test every window all the way up and down.
- Instrument cluster Cycle the key and watch the gauges sweep on startup; sticking or dead displays are a common Mk4 quirk.
- Transmission type The 5-speed manual is the bulletproof choice. If it is the 4-speed automatic, fluid service history matters more than mileage — confirm the type and drive it carefully.
- High-mileage diesel items Glow plugs, the coolant temperature sensor, and a soot-clogged EGR valve are typical wear items on a high-kilometre ALH — none catastrophic, but worth expecting.
What would make you walk
- No belt history, unknown mileage On an interference engine, buying with no timing belt documentation and no idea of the mileage is a gamble with the whole engine as the stake.
- Structural rust Rockers rusted through, soft floor pans, or a rotted subframe. On a unibody car, structural rust is not a repair — it is a different car.
- No inspection allowed A seller who refuses to let a TDI-aware mechanic put it on a hoist before money changes hands.