Question 1

Timing Belt Failure Risk

Accepted Answer

If the timing belt breaks, the valves collide with the pistons. The engine is destroyed. There is no warning -- the belt simply snaps and the engine stops instantly with catastrophic internal damage. The VG30 is an interference engine with a rubber timing belt that deteriorates with age and mileage. Nissan specified 100,000 km intervals, but many specialists recommend 80,000 km or 5 years, whichever comes first. Heat, oil contamination, and age degrade the belt regardless of mileage. Replace the timing belt, tensioner, idler pulleys, and water pump as a set. This is the Z32's most important scheduled maintenance item. Cost: $1,500--3,000 due to the extensive labour required to access the belt. The job typically takes 6--10 hours.

Question 2

Spark Plug Access (Rear Bank)

Accepted Answer

The rear three spark plugs become fouled, worn, or fail, causing misfires, rough running, and reduced power. The spark plugs wear normally -- but the rear bank plugs are buried under the intake plenum and are extremely difficult to access. Many owners defer the rear plug change because of the labour involved, which means the plugs run far beyond their service life. Remove the upper intake plenum to access the rear bank. Replace all six plugs simultaneously. This is a 2--4 hour job depending on experience. Cost: $200--500 at a workshop (mostly labour).

Question 3

Oil Leaks

Accepted Answer

Oil seepage and dripping from multiple points -- valve cover gaskets, rear main seal, oil pan gasket, timing cover, turbo oil lines (TT), power steering lines, and various sensors. The VG30 uses numerous rubber gaskets and O-rings that harden and shrink with age. The engine runs hot, accelerating seal degradation. The twin-turbo model has additional oil lines for the turbochargers that add more potential leak points. Systematic replacement of all gaskets and seals. The valve cover gaskets are the most accessible ($100--200 DIY). The rear main seal requires gearbox removal ($500--1,000). A full reseal is a major undertaking on the Z32 due to engine bay access. Budget $1,000--2,500 for a comprehensive reseal.

Question 4

Overheating

Accepted Answer

Temperature gauge climbs, particularly in traffic or on hot days. Coolant loss. Steam from under the bonnet. The Z32's cooling system is adequate when all components are fresh, but marginal when they're not. The radiator loses efficiency, the thermostat sticks, the water pump weeps, and the various coolant hoses (there are many) develop leaks. The twin-turbo model generates significantly more heat than the NA. Replace the radiator (aluminium upgrade recommended: $400--700), thermostat ($20--40), water pump (done with timing belt), and all coolant hoses. Total cooling system refresh: $500--1,000 beyond the timing belt service.

Question 5

Vacuum Line Deterioration

Accepted Answer

Boost fluctuations, poor throttle response, check engine light, erratic idle, boost creep (boost exceeding target), or inability to make boost. The twin-turbo system uses a complex network of vacuum lines to control the wastegates, boost solenoids, and various emissions devices. There are over 30 vacuum lines in the engine bay, most made of rubber that hardens, cracks, and splits after 30+ years. A single cracked vacuum line can cause cascading problems that are maddening to diagnose. Replace all vacuum lines with silicone hose. This is a tedious but straightforward job -- the hardest part is tracing each line and ensuring the routing is correct. Many Z32 owners replace the entire vacuum system in one session using a vacuum line replacement kit ($50--100 for the hose, plus a full day's labour). Cost: $50--100 DIY, $300--600 at a specialist.

Question 6

Turbocharger Wear

Accepted Answer

Excessive turbo whine, metallic grinding or rattling from the turbos, blue smoke under boost (oil passing through worn seals), or reduced boost pressure. The stock T25 turbochargers have a finite lifespan. After 150,000--200,000 km, the bearings and seals wear. Running the turbos on contaminated or insufficient oil accelerates wear dramatically. Shutting the engine off immediately after hard driving (instead of letting it idle to cool the turbos) also causes bearing damage. Rebuild or replace the turbochargers. Rebuilt stock turbos: $800--1,500 per pair. New aftermarket turbos: $1,500--3,000 per pair. Many owners upgrade to larger turbochargers at this point. Labour for turbo removal and refitting is significant due to engine bay access. Total cost: $2,000--5,000.

Question 7

Power Steering Line Fire Risk

Accepted Answer

Power steering fluid leaks onto the hot exhaust manifold or turbo housing. In extreme cases, the fluid ignites. The high-pressure power steering lines route near the exhaust on both sides of the engine. The rubber hose sections deteriorate from heat cycling, develop cracks, and begin to weep power steering fluid. The fluid contacts surfaces that can exceed 400 degrees Celsius. Replace the power steering lines with aftermarket steel-braided lines ($200--500) or new rubber lines. Inspect regularly. Any visible power steering fluid near the exhaust requires immediate attention.

Question 8

Third Gear Synchro Wear (Manual)

Accepted Answer

Grinding or crunching when shifting into 3rd gear, particularly on quick downshifts from 4th. May be more pronounced when cold. Third gear takes the most punishment in sporty driving. The brass synchro ring wears thin and can no longer match shaft speeds effectively. Gearbox rebuild with new synchro rings. Cost: $1,500--3,000 for a full rebuild. A used replacement gearbox is $800--1,500 but may have the same issue.

Question 9

Clutch Slave Cylinder Failure (Manual)

Accepted Answer

The clutch pedal goes soft or to the floor. Difficulty engaging gears. Clutch fluid on the gearbox bellhousing. The clutch slave cylinder is mounted on the outside of the gearbox bellhousing and is exposed to heat from the engine and exhaust. The seals fail with age. Replace the slave cylinder. It is relatively accessible on the Z32. Cost: $100--250 for the part, $200--400 for labour.

Question 10

Bushing Deterioration

Accepted Answer

Clunking, knocking, and general looseness in the suspension. Vague steering response. Uneven tyre wear. The car feels imprecise and wallowy. The Z32's multi-link suspension uses numerous rubber bushings that degrade after 25--35 years. The rear lower control arm bushings are typically the first to fail and among the hardest to replace. Replace all worn bushings. Polyurethane or Nismo uprated bushings are available for key locations. A full bushing replacement is a significant job -- budget $1,000--3,000 for parts, plus substantial labour.

Question 11

HICAS Failure

Accepted Answer

HICAS warning light on the dashboard. Strange rear-end behaviour at low speeds (parking manoeuvres). The rear wheels may track incorrectly. The HICAS (High Capacity Actively Controlled Steering) system uses hydraulic actuators, electronic sensors, and a separate power steering pump to steer the rear wheels. After 30+ years, the actuators leak, the sensors drift, and the system no longer functions correctly. Two options. Repair the HICAS system (expensive, parts increasingly scarce, $500--1,500+). Or delete it entirely with HICAS lock-out bars ($100--200), which convert the rear to conventional fixed steering. Most Z32 enthusiasts recommend deletion -- it simplifies the car, reduces maintenance, and many drivers prefer the handling with HICAS removed.

Question 12

T-Top Seal Leaks

Accepted Answer

Water enters the cabin during rain or car washes. Wet headliner, carpet, and footwells. Mould and corrosion follow. The T-top rubber seals harden and crack with UV exposure and age. The drain channels that carry water away from the T-top openings become blocked with debris. Replace the T-top seals ($300--600 for a full set). Clean the drain channels. If water has been entering for an extended period, inspect the floors for corrosion and the interior for mould.

Question 13

Dashboard Cracking

Accepted Answer

Cracks develop across the dashboard surface, typically starting above the instrument cluster and spreading outward. UV exposure and heat cause the dashboard material to shrink and crack. This is a universal Z32 problem, especially in Australian conditions. Dashboard replacement (used: $500--1,500 if you can find one; they are increasingly scarce), dashboard cap/overlay ($200--400), or professional dashboard repair/recovery ($400--800).

Question 14

Wiring Harness Deterioration

Accepted Answer

Intermittent electrical failures, random warning lights, non-functional accessories, and difficulty diagnosing faults. The Z32's wiring harness uses a large number of connectors and splices. Insulation becomes brittle with age and heat. Connector pins corrode, increasing resistance. Previous owners' modifications (stereos, boost controllers, aftermarket lighting) add spliced wires and non-standard connections. Systematic inspection and repair of the wiring harness. Clean and reseat connectors, replace damaged sections. A full harness replacement is possible but extremely labour-intensive. Cost: $200--500 for targeted repairs, $2,000--5,000 for comprehensive rewiring.

Question 15

Mass Air Flow Sensor Failure

Accepted Answer

Poor throttle response, hesitation, rich or lean running, check engine light. The MAF sensor deteriorates with age and contamination. Hot-wire type sensors are sensitive to oil vapour from the crankcase ventilation system. Replace the MAF sensor. OEM Nissan units are preferred. Cost: $200--400 per sensor (the TT has two).

300ZX (Z32)

300ZX (Z32) known problems