Opel Signum
Isuzu-developed 3.0-litre V6 diesel with chain drive – purely a long-distance engine. Two serious weaknesses: cylinder liner drop in the block and contaminating metering unit of the high-pressure pump. Early production up to around 2005 significantly more problematic.
Signum diesel top
130 kW V6 diesel – the best engine in the Signum for long-distance trips.
Engine Weaknesses 4
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
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
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
A faulty metering unit causes increased soot output, which quickly destroys the EGR valve. Both faults often occur together. Cleaning with fuel additives can delay the problem.
Symptoms: Power loss, increased fuel consumption, limp mode, visible soot on intake tract
Vehicle Weaknesses 12
Electronically controlled ZF-Sachs dampers fail around 90,000–130,000 km. OEM parts over 1,600 €; aftermarket from 150 € per unit.
At the rear roof rail end cap, moisture penetrates between two sheet metal layers causing corrosion.
Cold solder joints in the CIM cause intermittent warning lights without actual fault. Diagnosis requires specialist equipment (Tech2).
On the Signum 1.9 CDTI the EGR valve and swirl flaps clog with soot deposits, causing power loss and smoke. Removal and cleaning costs approx. 100–200 €; replacement is more expensive.
The main radiator of the Signum rusts and leaks from approx. 150,000 km. Radiator replacement requires complete front-end disassembly including AC condenser.
KBA recall for Vectra C and Signum (build years 2002–2007): insufficient spring force in the handbrake lever ratchet.
Track rods and track rod ends show play from approx. 100,000 km. Parts are inexpensive but wheel alignment must be done afterwards.
Rotary knob potentiometers develop contact weaknesses through cold solder joints. Blower occasionally fails completely.
Even without IDS, shock absorbers wear from approx. 100,000–130,000 km. Short-trip use accelerates wear.
The electro-hydraulic steering rack (EHPS) of the Signum leaks oil from approx. 140,000 km. Dashboard warning; sudden loss of steering assistance possible when oil level empty.
On the Signum water enters through leaking tailgate seals or rear light seals into the boot. Spare wheel well fills up.
In the Signum the adhesive between the headliner support rails and fabric deteriorates after 15–20 years due to heat. Foam crumbles; fabric droops.
