IsItAGoodCar
Reliability Guide

Common Problems with the
1990 Lamborghini Diablo

The Diablo launched as the replacement for the Countach, featuring a mid-mounted 5.7-litre V12 producing 485bhp, rear-wheel drive, and iconic pop-up headlamps. UK deliveries began via Portman Concessionaires.

What changed for 1990

  • •UK market launch of original Diablo
  • •Mid-mounted 5.7-litre 48-valve V12 producing 485bhp
  • •Marcello Gandini styling with Chrysler interior revisions
  • •Top speed exceeding 202mph making it the fastest production car in 1990

Common MOT watch-outs

  • !Exhaust emissions failure on early Weber-Marelli injection
  • !Severe headlamp aim misalignment from worn pop-up linkage
  • !Suspension wishbone ball joint and bush play
  • !Ineffective handbrake on rear Brembo calipers
3
Known Issues
2
Serious
1
Moderate
0
Minor

All Known Issues

Single-Plate Clutch Wear and Slave Cylinder Pull-Rod Failure

SeriousGearbox & Transmission

The Diablo's 5.7-litre and 6.0-litre V12 engines transfer up to 457 lb-ft of torque through a single dry-plate clutch. Due to high vehicle mass and heavy low-speed gearing, the clutch disc experiences rapid friction material wear during stop-start UK driving, rarely lasting beyond 20,000 to 25,000 miles. Furthermore, pre-1998 cars employ a pull-type hydraulic slave cylinder mechanism where the internal operating rod is prone to fatigue fractures or hydraulic seal blow-out, suddenly leaving the driver unable to disengage the clutch. Replacing the clutch assembly requires dropping the rear suspension, differential, and V12 powertrain, resulting in substantial specialist labour bills.

Est. Repair Cost: £3,500–£6,500
Warning Signs:

Clutch pedal sticking to the floor or failing to return, Difficulty engaging first gear or reverse from a standstill, Severe clutch slip under hard acceleration in third or fourth gear, Burning clutch smell after reversing or hill-starts

What to Inspect:
  • Test clutch pedal resistance and bite point consistency across several shifts
  • Inspect the transmission bellhousing for leaking hydraulic fluid from the slave cylinder
  • Check service history invoices to establish the exact mileage on the current clutch disc
  • Verify whether the slave cylinder was updated to the revised push-type arrangement
Verified by IsItAGoodCar Research TeamUpdated

Timing Chain Hydraulic Tensioner Failure and Overrun Rattle

SeriousEngine

Early 1990–1994 Lamborghini Diablo 5.7-litre V12 engines used oil-pressure-fed hydraulic timing chain tensioners that suffered from a dangerous design flaw: engine oil pressure pulsations progressively ratcheted the tensioners tighter against the guide rails until excessive tension caused one or both timing chains to snap. This catastrophic failure resulted in complete valve-to-piston collision, destroying cylinder heads, pistons, and liners. From 1994, Lamborghini superseded these with mechanical ratchet tensioners and issued service bulletins to retrofit earlier engines. In addition, high-mileage Diablos can experience timing chain stretch, producing an audible rattle on the overrun.

Est. Repair Cost: £3,000–£8,000
Warning Signs:

Audible metallic rattling from the front or centre of the engine on throttle overrun, Rough idle and uneven running caused by camshaft timing drift, Illuminated check engine light on later multi-point management systems, Total engine seizure in the event of timing chain breakage

What to Inspect:
  • Inspect service documentation for proof of mechanical tensioner retrofit on pre-1994 cars
  • Rev the engine up to 3,500 rpm and listen carefully as the revs fall back to idle
  • Check for oil leaks around the timing chain cover gaskets
  • Commission a specialist borescope and valve clearance check before purchase
Verified by IsItAGoodCar Research TeamUpdated

Galvanic Body Corrosion and Steel Spaceframe Rust

ModerateBodywork & Rust

The Diablo construction combines hand-beaten aluminium body panels mounted over a rectangular-tube steel spaceframe, with composite carbon-fibre used for the bumpers, sills, front bonnet, and engine cover. Inadequate galvanic barrier protection at the factory allows electrolytic corrosion to occur where the aluminium skin makes direct contact with the steel subframes. When exposed to damp British roads and winter salt spray, moisture is trapped within unsealed seams, causing galvanic blistering of the aluminium paintwork and structural rusting of the tubular steel chassis. Areas worst affected include the lower door bottoms, outer sill mounting points, front boot floor, and fuel filler pocket.

Est. Repair Cost: £1,500–£5,000
Warning Signs:

Bubbling paintwork and white aluminium oxide powdery deposits along door bottoms, Visible rust staining on the steel tubular floor structure inside the front luggage compartment, Blisters appearing beneath the paint around the fuel filler flap recess, Distorted door panel alignment causing doors to catch against composite sills

What to Inspect:
  • Carefully inspect the bottom hem edge of both scissor doors with a torch
  • Lift front luggage compartment carpets to examine the painted steel floor and tubular nodes
  • Check the seam where the rear aluminium wings meet the steel chassis frame
  • Inspect inside the fuel filler neck housing for corrosion creeping beneath the rubber seal
Verified by IsItAGoodCar Research TeamUpdated

Buying Tips for 1990 Lamborghini Diablo

  • Check for retrofitted mechanical timing chain adjusters
  • Be prepared for very heavy unassisted steering at parking speeds
  • Inspect aluminium body panels for galvanic corrosion bubbles at sills
1991–1998
Check a 1990 Lamborghini Diablo by Registration