Opel Signum
High-output variant of the 1.9 CDTI with known structural weaknesses: turbocharger and exhaust manifold are one assembly, making repairs more expensive. Swirl flaps in the intake manifold are the most common cause of failure. Reliable with documented maintenance at high mileage.
Signum diesel top
110 kW in the Signum – finally adequate diesel power for the long-distance saloon.
Engine Weaknesses 5
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.
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.
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.
The EGR valve cokes up from exhaust gas recirculation, especially with short-trip use. Heavy coking can lead to a permanently open valve and trigger a cascade of further faults.
Symptoms: Engine warning light, power loss, rough idle, limp mode in severe cases, fault codes P0400–P0409.
Common-rail injectors show increased return volumes at high mileage through wear of the precision mechanics. Specialist repair is often cheaper than buying new.
Symptoms: Rough and uneven engine running at idle, heavy knocking on cold start, uneven cylinder contribution, increased fuel consumption.
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.
