Hyundai CRDi (badge, not an engine)

CRDi is a badge, not an engine — it stands for common-rail direct injection, which by now describes every diesel sold.

Our rows show it on 1.1 to 3.0 litres across Hyundai and Kia, covering at least the D4FA, D4FC, D4FD, D4EA, D4EB, D4CB, D4HB and S6DA families — eight designs under one badge, three-cylinder to V6.

The code is stamped on the block and is what to search. D4CB is the big four-cylinder in the vans and pickups; D4FB/D4FC are the 1.6 in the small cars; D4HB the 2.2 in the SUVs. They share a badge and a fuel system philosophy and very little else.

Two things recur across the family and are worth stating once:

• The D4CB's reputation is the timing chain and the balance shafts. A rattle on a cold start is the chain; a heavier knock under load on high-mileage vans is the balance-shaft bearings, and that one is terminal if ignored because it feeds the oil pump.
• The DPF and EGR story is the ordinary one, and short journeys ruin both — but Hyundai's regeneration strategy is unusually sensitive to being interrupted, and a car whose regeneration is repeatedly cut short by a short journey accumulates fuel in the sump. That dilutes the oil, and an oil level that has RISEN on the dipstick is the tell.