Kia 1.7 CRDi
Evolved diesel with slightly more displacement for better pulling power. Smoother than the 1.6 — DPF problems on short trips possible.
Long-distance diesel with character
141 hp CRDi in the Optima JF is a good compromise of efficiency and performance for long-distance drivers. No sports diesel, but refined.
Engine Weaknesses 7
The electronically controlled EGR valve of the D4FD becomes packed with soot deposits and sticks. Cleaning the valve and intake tract is routinely due at around 80,000–100,000 km.
Symptoms: Judder at low load, engine warning light EGR fault, poor performance in the lower rev range
Bosch direct injectors of the D4FD can be damaged by poor fuel quality. Copper sealing washers must be renewed every 100,000–150,000 km, otherwise combustion gases escape into the cylinder head.
Symptoms: Hard starting, uneven running, increased fuel consumption, smoke on start-up
From around 150,000 km the D4FD's DPF becomes problematic: blockage causes regeneration failures and oil dilution in the crankcase from fuel injected during forced regeneration.
Symptoms: DPF warning light, engine power reduction, increased fuel consumption, oil level rises (diesel mixes into oil)
The Garrett turbo of the D4FD can cause boost loss through a faulty variable vane mechanism or a seized vacuum actuator. The vacuum valve (part no. 35120-2A400) is a known wear item.
Symptoms: Loss of boost pressure, power loss under load, fault code P0299 (turbo underboost), occasional overboost flutter
The 1.7 CRDi suffers severely from DPF problems in predominantly short-trip use. Documented in Polish forums: regeneration every 50–80 km instead of the normal 250–300 km, oil level rises from fuel dilution.
Symptoms: Very frequent DPF regeneration, oil level rising due to fuel dilution, power drop, DPF warning light, limp-home mode.
The D4FD's EGR valve tends to carbon up, leading to power loss and increased fuel consumption. Typical issue of the 1.7 CRDi unit, frequently occurring alongside DPF problems.
Symptoms: Power loss, judder under partial load, fault code P0401/P0404, limp-home mode.
The 1.7 CRDi is prone to premature DMF fatigue like the other U-series diesels. The DMF wears quickly particularly in constant urban use or with an aggressive clutch style.
Symptoms: Vibration and rattling on pull-away and cold start, jerky gear changes.
Vehicle Weaknesses 6
Over 500,000 Kia Optima vehicles were recalled due to faulty ABS systems. A short circuit in the anti-lock braking system can cause a fire. A further recall concerned the hydraulic ABS valve, which can lead to leaks and short circuits.
The Optima JF's suspension is prone to spring breakage, which creates an unsafe driving condition. Coil springs, particularly on the rear axle, break without warning. Especially common on vehicles that are used frequently on poor roads.
Brake calipers and discs on the Optima JF show a strong tendency to rust. Uncoated brake disc faces rust heavily after rain. Stuck calipers lead to uneven pad wear and increased fuel consumption.
On the Optima JF, owners report mould forming on the AC evaporator, causing a musty smell when switched on. According to forum reports, the system needed cleaning multiple times.
On the Optima JF, a noticeable resistance point in the steering is reported at temperatures below 13°C, as if someone were holding the steering column. On some vehicles the entire steering had to be replaced.
The infotainment system on the Optima JF occasionally freezes and needs restarting. The reversing camera responds with a delay or shows no image. Software issues can be partially resolved by dealer updates.
Reports & Tests
2489 owner complaints filed with NHTSA (2015–2020). Most reported: Engine (1460), Other (367), Electrical (316).