Seat Leon
81 kW four-cylinder CNG engine in dual-fuel petrol/CNG operation. Check CNG gas lines for leaks; shorten oil change intervals in CNG mode. Low running costs with good gas infrastructure.
Leon TGI — eco-friendly and sensible
With 81 kW running on CNG the Leon 5F TGI drives economically and with low emissions. Petrol mode is available as a reserve. Performance is adequate for daily use, and sporting driving is outside the concept. Smart for commuters with access to CNG infrastructure.
Engine Weaknesses 9
On Seat Leon TGI models (CPWA) from model year 2018, gas leaks were documented from gas line fittings tightened with insufficient torque. A recall was carried out for affected vehicles. Gas leaks must be treated as safety-relevant.
Symptoms: Gas smell in the engine bay or cabin, elevated CNG consumption, gas warning light
On the g-tron engine, valve stem seals wear earlier than with petrol operation due to the higher thermal load from CNG combustion. Replacement documented at approx. 80,000 and 120,000 km.
Symptoms: Oil vapour from exhaust especially on cold start, elevated oil consumption, misfires in CNG mode
CNG operation requires precise lambda control (λ=1). Lambda sensor heating elements can overheat from faulty software control and fail prematurely.
Symptoms: Rough idle in CNG mode, engine check light, ECU switches to petrol operation
CNG composite tanks are subject to mandatory gas system inspection (GAP) every 48 months. Inspection must be performed by certified specialists. Tanks have a 20-year service life; replacement is very expensive.
Symptoms: No driving symptoms, but vehicle inspection fails without valid GAP certificate
At high mileages from approx. 150,000 km misfires occur in CNG mode. Cause: worn spark plugs or ignition coils that must be replaced earlier in CNG operation.
Symptoms: Juddering and misfires exclusively or predominantly in CNG mode, automatic switch to petrol by the ECU
The pressure tanks must be inspected every 4 years. A missed inspection means a driving ban in CNG mode and can cause problems when selling.
Symptoms: None — administrative risk; check service booklet
The CPWA CNG engine requires oil changes every 15,000 km at the latest despite the long-life service indicator. CNG operation leads to slightly elevated oil condensation ingress. Ignored intervals can promote bearing damage.
Symptoms: No specific symptom, but elevated engine wear risk if oil change interval is exceeded
The gas injection valves wear after 150,000–200,000 km. A defective valve causes power loss in CNG mode; the engine switches to petrol. Servicing by a CNG specialist is required.
Symptoms: Automatic switch to petrol mode, rough running on CNG, elevated consumption
As with all EA211 TSI engines with direct injection, oil residues deposit on the intake valves. Cleaning is recommended at higher mileage.
Symptoms: Slight power reduction, rough idle, elevated fuel consumption
Vehicle Weaknesses 8
Multiple recalls: child locks on rear doors can deactivate while driving (2015–2016). Airbag modules were also recalled.
On 2014 build-year cars, screws on the camshaft adjuster can come loose and migrate into the engine. The timing belt tears and the engine is destroyed. Manufacturer recall (TPI 2038019/4) — verify completion on any used car.
Seat installs constrictions in the panoramic roof drain hose for noise damping purposes. These constrictions become blocked and divert water into the interior.
Gradual coolant loss occurs on 1.6 TDI and 2.0 TDI Leon 5F models. The usual cause is a defective EGR cooler or a cracked coolant hose.
Springs and shock absorbers on the Leon 5F show above-average wear even at the first roadworthiness inspection. Shock absorbers in particular are frequently flagged.
The headlights of the Leon 5F are prone to developing micro-cracks in the lens cover. At the roadworthiness inspection a complete headlight replacement can be required.
A configuration error in the body control module (BCM) prevents detection of failed front LED indicators. Affects cars produced November 2016 to October 2019. Software update at the dealer is free of charge.
Interior trim panels and footwell covers in the Leon 5F are prone to rattling and squeaking noises. Door trim panels and footwell covers are particularly affected.
Reports & Tests
The third Leon generation performs more solidly at the roadworthiness inspection than its predecessor. Even at the first mandatory check coil springs, shock absorbers, and headlights attract attention; micro-cracks in the headlight lenses can necessitate a complete replacement.
