Opel Signum Signum
Weaknesses, engine ratings and buying advice
The Opel Signum (2003–2008) was Opel's attempt to establish an upper-middle-class model alongside the Vectra C — same Epsilon platform, but 14 cm more wheelbase and a noticeably more luxurious cabin concept. It never really sold, which is why few well-maintained examples are on the market today. Finding one means getting a lot of car for very little money — provided the engine choice is right.
Market overview: The Signum is a hidden gem for long-distance drivers. A huge boot with variable floor, comfortable seats, quiet interior. Parts supply is identical to the Vectra C, workshops have experience. The body still does not look dated in 2026 — the design has aged better than the contemporary Vectra.
Engine choice: The Z19DTH (1.9 CDTi, 110 kW/150 PS) is the best all-rounder — strong mid-range, economical (6–7 litres real on the motorway), and durable past 300,000+ km with regular oil changes. But: EGR valve cokes with short trips (300–600 EUR), turbocharger can fail early on 2005–2007 models (800–2,000 EUR). The smaller Z19DT (88 kW/120 PS) is slightly underpowered for 1,600+ kg. The Y30DT (3.0 V6 CDTi, 130 kW/177 PS) is the long-haul king — silky smooth, but timing chain stretches from 150,000 km (2,000–3,500 EUR) and injectors cost 400–600 EUR each. Petrol: Z22YH (2.2 Direct, 114 kW/155 PS) — decent, but timing chain from 60,000–90,000 km (900–3,000 EUR). Z20NET (2.0 Turbo, 129 kW/175 PS) — brisk, turbo holds with sensible oil changes. The V6 petrols Z28NEL/Z28NET (2.8 Turbo, 169–184 kW) and Z32SE (3.2 V6, 155 kW) are rare — impressive, but timing chain costs and consumption (11–14 litres) are deterrents. The Z18XER (1.8, 103 kW) is simply too weak for the heavy Signum.
Weak points: Electrics are the recurring theme — CIM module (steering column module) fails, window regulators die in sequence, central locking plays up. Rust on rear wheel arches and sills under the rubber strip — better than the Astra G, but relevant after 15+ years. Coolant expansion tank cracks (an Opel classic, 20–60 EUR). Rear shock absorbers wear faster than on the Vectra C due to the higher weight.
Test drive checklist: Z19DTH cold start (turbo whine?), Z22YH cold start (chain rattle?), test all window regulators, CIM module (indicators, horn, wipers simultaneously), coolant level and colour, inspect underside sills and wheel arches for rust.
Buying advice: 2005–2007 with 120,000 km 2,500–5,500 EUR. V6 CDTi 3,500–6,500 EUR. V6 Turbo petrol 3,000–5,000 EUR. Insider pick: Z19DTH (1.9 CDTi, 150 PS) with 6-speed manual and leather trim — that is the most sensible combination. Avoid Easytronic categorically. Long-distance drivers who need space get more here than from any comparably priced Passat.
177 PS
Signum · Diesel
Signum diesel top
Fun to Drive!177–184 PS
3.0L CDTI V6 Diesel
6 weaknesses
Stay Away!Engine Overview
The Opel Signum Signum is available with 8 engine variants — from 101 to 280 hp. 1 variants had engine changes — the model year is crucial.
Robustly designed Fiat diesel (1.9 L CDTI, 88 kW, GM licence), fitted in the Astra H, Zafira B and Vectra C. Reliable to high mileages with regular oil changes and motorway use. Critical weak points are the EGR valve (carbonises from 100,000 km), DPF with short-trip use, and the dual-mass flywheel (rumbling noise when warm). The simpler 8V cylinder head is robust — a good commuter diesel overall.
- !! Dual mass flywheel worn from 110,000 km
The dual mass flywheel shows typical wear from around 80,000–150,000 km, especially in city driving. Replacement requires gearbox removal and is usually combined with clutch replacement.
Symptoms: Rattling or clattering at low revs below 1,200 rpm, shaking or juddering when pulling away, noise when engaging a gear that disappears when the clutch is pressed. - !! Timing belt breaks when replacement interval is exceeded from 140,000 km
The Z19DT uses a timing belt with a replacement interval of 120,000–150,000 km or 10 years. Exceeding this risks belt failure with immediate engine damage from valve contact. Simultaneous water pump replacement is mandatory.
Symptoms: Possibly squealing or faint clattering from timing cover beforehand. When it breaks: engine stops immediately and will not restart. - !! EGR valve coked up from 120,000 km
The EGR valve clogs with soot from exhaust gases, especially with short-trip use. The valve sticks open or closed, triggering the engine warning light and power loss.
Symptoms: Engine warning light after cold start, rough idle, delayed throttle response, power loss at low revs, occasional stalling at standstill.
+ 1 more engine weaknesses + vehicle weaknesses
High-output 16V variant of the 1.9 CDTI (110 kW) with known structural weaknesses: turbocharger and exhaust manifold form a single unit, which makes repairs more expensive. The variable swirl flaps in the intake manifold are the most frequent and costly cause of damage — they can break off and enter the combustion chamber. With documented maintenance history and the swirl flap update completed, this is a strong and reliable diesel.
- !! Swirl flap failure in intake manifold from 100,000 km
Plastic bushings on the swirl flap shaft wear and break out. Flaps can snap off and be ingested by the engine. Revised intake manifold fitted from build date 02/2007.
Symptoms: Vehicle enters limp mode, power loss below 2,500 rpm, fault code P1109 or P2075, engine warning light permanently on. - !! Turbocharger failure (Garrett GT1749MV) from 120,000 km
The Garrett turbocharger is structurally connected to the exhaust manifold, making repairs more expensive. For build years 2006–2007, the cause was an oil supply hollow bolt with too fine a mesh (15 µm instead of 40 µm).
Symptoms: Whistling or hissing sound from engine bay, power loss when accelerating, black smoke from exhaust, oil in air filter housing. - !! Dual mass flywheel and M32 gearbox from 120,000 km
In addition to DMF wear, bearing wear also occurs in the M32 gearbox (5th/6th gear). Both faults often occur together, requiring an extensive repair.
Symptoms: Humming or grinding at higher speeds in 5th/6th gear, rattling at idle, shaking when pulling away, clattering when clutch is released.
+ 2 more engine weaknesses + vehicle weaknesses
Isuzu-developed 3.0-litre V6 diesel with chain drive — purely a long-distance engine for the Signum and Vectra C. Two serious weaknesses: cylinder liner drop in the block (requires engine replacement) and a contaminating metering unit on the high-pressure fuel pump. VTG turbo actuator frequently fails from 150,000 km. Early production up to around 2005 is significantly more problematic than later examples. Only purchase with a complete service book.
- !! Cylinder liner sinking — compression into cooling system from 150,000 km
Design fault: cylinder liners sink in the block, compression escapes into the cooling system. The result is overheating and total engine failure. Occurs from around 130,000–200,000 km; earlier build years more frequently affected.
Symptoms: Coolant warning light, hissing sound when opening the coolant reservoir, rapid coolant loss, sudden temperature spike - !! High-pressure pump metering unit clogged from 120,000 km
The Bosch high-pressure pump metering unit clogs with manufacturing residues. Production up to approx. September 2005 particularly susceptible. Power loss and juddering; secondary EGR valve damage from increased soot output.
Symptoms: Severe power loss and juddering, limp mode, fault code P0251 or P0090 - !! M32 gearbox: bearing failure from 150,000 km
The M32 manual gearbox suffers from well-known bearing failures. Growling or grinding at certain engine speeds, often in 4th or 5th gear. Fundamental design issue with this gearbox.
Symptoms: Growling or grinding noise at certain engine speeds and gears, vibrations in gear lever
+ 3 more engine weaknesses + vehicle weaknesses
Solid naturally aspirated engine (1.8 L, 103 kW) from the GM Ecotec series, fitted in the Astra H/J, Zafira B and Vectra C. Reaches 250,000 km and beyond without problems with regular care. Main weaknesses are the electronically controlled thermostat (opens sporadically at the wrong time) and elevated oil consumption at high mileage from worn piston rings. Check the VVT actuator condition. Timing belt change with water pump every 150,000 km.
- !! Timing chain and tensioner worn from 130,000 km
The timing chain is theoretically maintenance-free but can stretch prematurely with neglected oil changes. Hydraulic chain tensioner and guide rails wear depending on maintenance history between 68,000 and 200,000 km.
Symptoms: Metallic rattling or clattering especially on cold start, easing as it warms up. Engine sounds 'like a diesel'. Oil pressure warning light in severe cases. - !! Camshaft adjuster failure (INA type) from 80,000 km
The Z18XER shares the same INA variable valve timing adjuster design flaw with the Z16XER. Broken rotor blades cause oil pressure loss and incorrect timing. Cold-start rattle is the early warning sign. Opel field service directive available. Replacement strongly recommended during timing belt service — same labor involved.
Symptoms: Cold-start rattle, P0011/P0014, power loss when cold - !! Electric thermostat faulty from 100,000 km
The map-controlled thermostat from Wahler/Pierburg fails through seal ring failure or electrical fault. If it fails in the closed position, overheating threatens.
Symptoms: Heater barely warm (thermostat stuck open), temperature gauge climbs unusually quickly into the red zone, coolant loss from faulty seal ring.
+ 2 more engine weaknesses + vehicle weaknesses
Reliable turbopetrol engine (129 kW) from the Ecotec family, fitted in the Vectra C, Signum and Saab 9-3. The chain tensioner on early pre-facelift engines up to 2008 is a known weak point — preventive replacement with the revised component (from MY 2009, part no. 12608580) is recommended. Turbocharger and boost pressure regulation are long-lived on well-maintained examples. A solid all-round turbopetrol with good torque.
- !! Timing chain stretched / tensioner faulty (pre-facelift) from 75,000 km
Pre-facelift engines have a hydraulic chain tensioner that can seize. The auxiliary chain guide rail snaps off; broken pieces fall into the oil sump. From model year 2009, Opel fitted the revised tensioner (part no. 12608580).
Symptoms: Rattling or clattering immediately after cold start, easing after approx. 30 seconds; engine warning light on advanced damage - !! Turbocharger failure at high mileage from 150,000 km
With neglected oil supply or after bypass valve problems, the turbocharger can fail. A new unit from an Opel dealer costs approx. 1,250 EUR without fitting. Labour-intensive as turbo removal requires many additional tasks.
Symptoms: No boost pressure, severe power loss at higher revs, whistling or rattling noise from turbo, blue exhaust smoke - !! Bypass valve membrane torn — boost pressure loss from 90,000 km
The bypass valve membrane develops a tear. The turbocharger can no longer regulate boost pressure correctly. The fault occurs intermittently and can temporarily disappear before becoming permanent. Two valves fitted: one on the turbo, one on the throttle body.
Symptoms: Intermittent power loss under load, bypass valve regulation out of target range fault message, delayed response when accelerating
+ 1 more engine weaknesses + vehicle weaknesses
Direct-injection variant (114 kW) of the 2.2-litre Ecotec with elevated fuel system pressure, fitted in the Vectra C and Signum. The high-pressure fuel pump is the most frequent and most expensive single weak point — a failure can contaminate the entire fuel circuit. The EGR valve carbonises quickly and causes power loss. Important: this engine is not E10-compatible. Only use Super or Super Plus grade fuel.
- !! High-pressure pump faulty from 110,000 km
When faulty, the high-pressure pump delivers insufficient fuel to the common rail. Cause is often oil sludge deposits or a stuck pressure control valve. E10 fuel accelerates wear considerably. Rail pressure below 600 kPa at idle is an indicator.
Symptoms: Juddering and misfires especially at high revs and on the motorway; engine cuts out when accelerating from standstill; limp mode - !! Timing chain stretch from 115,000 km
On the Z22YH, the timing chain also drives the high-pressure pump, placing more load on it than on the Z22SE. Chain stretch typically sets in between 100,000 and 140,000 km. Improved tensioner design available.
Symptoms: Rattling on cold start in the timing chain area; engine warning light with fault code for implausible camshaft position; phase error in fault memory - !! EGR valve coking / actuator gear failure from 80,000 km
The electric EGR valve clogs particularly quickly from direct injection. Heavy soot deposits can damage the actuator motor gears after just 10,000 km. Opel offered a field fix (EGR deactivation + software update, approx. 300 EUR).
Symptoms: Noticeable power loss especially in the lower rev range; increased fuel consumption; black deposits in intake manifold
+ 1 more engine weaknesses + vehicle weaknesses
Base V6 turbo (188 kW) without variable camshaft timing, fitted in the Vectra C OPC and Signum V6 Turbo. Same block and chain drive as the more powerful Z28NET — the timing chain issue (primary chain stretches, tensioner fails) is identical and should be monitored from 80,000 km onwards. Turbocharger wear at higher mileages is expected. Check the oil cooler gasket. A powerful engine with limited production numbers.
- !! Timing chains stretch (V6 turbo) from 130,000 km
Both timing chains on the 2.8 V6 stretch from 100,000–150,000 km. Oil channel blockage can accelerate the wear. Preventive replacement recommended.
Symptoms: Rattling on cold start, engine warning light, limp mode, valve damage in extreme cases - !! Misfires / juddering at idle from 80,000 km
The V6 is prone to misfires and juddering at warm idle. Replacing spark plugs and coils does not always provide a permanent fix.
Symptoms: Juddering at idle (warm), brief jolting of the vehicle, lambda values within normal range - !! Turbocharger wastegate rattling from 120,000 km
Wastegate actuator and turbine shaft deteriorate at higher mileage. Power loss and fluctuating boost pressure.
Symptoms: Uneven boost pressure, power loss in the mid-range, occasional limp mode
+ 1 more engine weaknesses + vehicle weaknesses
2.8-litre V6 bi-turbo with variable camshaft timing — a concept that delivers: broad torque band from 1,800 rpm, effortless power delivery across the entire rev range. The unmistakable sound of a wound-up V6 with turbo flutter on lift-off is part of the experience. Timing chains are the most important maintenance concern: elongation is possible from 130,000 km, with repair costs of 2,000–4,000 EUR. Idle surging despite new ignition components is a known and hard-to-resolve phenomenon.
- !! Timing chains stretch (V6 turbo VCT) from 130,000 km
Both timing chains stretch and cause camshaft phase offset. Typical from 100,000–150,000 km. Oil channel blockage accelerates the wear.
Symptoms: Rattling on cold start (disappears after 30 sec.), engine warning light, limp mode, valve damage - !! Misfires / juddering at idle from 80,000 km
The Z28NET is prone to misfires and juddering at warm idle. Spark plugs and coils have been replaced without lasting success.
Symptoms: Juddering at idle (warm), brief jolting of the vehicle - !! Turbocharger wastegate / boost pressure loss from 120,000 km
Wastegate actuator and turbine shaft on the V6 turbocharger deteriorate. Power loss and fluctuating boost pressure result.
Symptoms: Uneven boost pressure, power loss in the mid-range, occasional limp mode
+ 1 more engine weaknesses + vehicle weaknesses
Naturally aspirated V6 (3.2 L, 155 kW) in the Vectra C GTS and Signum. A high-quality engine with refined running characteristics and linear power delivery. Known for oil cooler leaks that introduce coolant into the oil — regularly check for emulsion on the oil filler cap. The cylinder head gasket is the second known weak point. Timing chain is long-lived. With an intact cooling circuit, a reliable and pleasantly smooth six-cylinder.
- !! Oil cooler leaking (between cylinder banks) from 100,000 km
The oil-water cooler located between the cylinder banks becomes porous and mixes oil with coolant. Repair is complex due to the V6 geometry.
Symptoms: Oil in coolant (brown emulsion), coolant consumption with no visible leak, steam from engine bay - !! Head gasket faulty from 130,000 km
The head gasket gives way at high mileage. Both sides of the V6 must be treated, making the repair very labour-intensive.
Symptoms: Heavy oil loss at exhaust manifold, coolant loss, white exhaust gases - ! Cam cover and oil pressure switch leaking from 80,000 km
Cam cover gaskets and oil pressure switch leak regularly. Escaping oil can migrate along the wiring loom into the ECU.
Symptoms: Visible oil seeping from cam cover, oil spots under vehicle, in the worst case ECU failure
+ 1 more engine weaknesses + vehicle weaknesses
Vehicle Weaknesses
| Weakness | Cost | |
|---|---|---|
| IDS electronic dampers worn Electronically controlled ZF-Sachs dampers fail around 90,000–130,000 km. OEM parts over 1,600 €; aftermarket from 150 € per unit. Symptoms: Harsh ride, fault message, IDS warning light, poor suspension. from 100,000 km | Medium | |
| Track rods worn Track rods and track rod ends show play from approx. 100,000 km. Parts are inexpensive but wheel alignment must be done afterwards. Symptoms: Steering play, pulling under braking, rattling from the front when steering. from 110,000 km | Low | |
| Shock absorbers worn (standard suspension) Even without IDS, shock absorbers wear from approx. 100,000–130,000 km. Short-trip use accelerates wear. Symptoms: Pitching over road waves, persistent bounce, uneven tyre wear, strong nose-dive under braking. from 120,000 km | Low |
Alternatives
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Known Problems and Issues +
A total of 53 weaknesses have been documented for the Opel Signum Signum (2003–2008) — 40 engine-related and 13 vehicle-related. 3 problem engines: Z22YH (2.2L 16V Direct), Z19DTH (1.9L CDTI), Y30DT (3.0L CDTI V6). Typical issues affect Suspension, Rust, HVAC, Electronics.
Signum (Y30DT, 2003–2008) — Stay Away!: Cylinder liner sinking — compression into cooling system, High-pressure pump metering unit clogged, M32 gearbox: bearing failure. Power: 177–184 PS.
Signum (Z19DT, 2004–2008) — Be Careful: Dual mass flywheel worn, Timing belt breaks when replacement interval is exceeded, EGR valve coked up. Power: 120 PS.
Signum (Z19DTH, 2004–2008) — Stay Away!: Swirl flap failure in intake manifold, Turbocharger failure (Garrett GT1749MV), Dual mass flywheel and M32 gearbox. Power: 150 PS.
Signum (Z20NET, 2003–2008) — Be Careful: Timing chain stretched / tensioner faulty (pre-facelift), Turbocharger failure at high mileage, Bypass valve membrane torn — boost pressure loss. Power: 175 PS.
Signum (Z32SE, 2003–2005) — Be Careful: Oil cooler leaking (between cylinder banks), Head gasket faulty, Cam cover and oil pressure switch leaking. Power: 211 PS.
Signum (Z22YH, 2004–2008) — Stay Away!: High-pressure pump faulty, Timing chain stretch, EGR valve coking / actuator gear failure. Power: 155 PS.
Signum (Z18XER, 2005–2008) — Be Careful: Timing chain and tensioner worn, Camshaft adjuster failure (INA type), Electric thermostat faulty. Power: 140 PS.
Signum (Z28NEL, 2005–2008) — Be Careful: Timing chains stretch (V6 turbo), Misfires / juddering at idle, Turbocharger wastegate rattling. Power: 230 PS.
Signum (Z28NET, 2006–2008) — Be Careful: Timing chains stretch (V6 turbo VCT), Misfires / juddering at idle, Turbocharger wastegate / boost pressure loss. Power: 250–256 PS.
What to watch out for with the Opel Signum? See the detailed listing of all engine and vehicle weaknesses in the sections above.
Frequently Asked Questions
What problems and weaknesses does the Opel Signum Signum have? +
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Last updated: February 2026 · All information without guarantee