300ZX (Z32)

1989-2000 / Coupe / Convertible / Japan

All 300ZX (Z32) problems All workshop issues

Common Twin-Turbo System (VG30DETT Only)

Vacuum Line Deterioration

Symptoms

Boost fluctuations, poor throttle response, check engine light, erratic idle, boost creep (boost exceeding target), or inability to make boost.

Cause

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.

Fix

1 Replace all vacuum lines with silicone hose. This is a tedious but straightforward job -
2 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

Cost mentioned in fix

$50Cost: $50$300

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// More 300ZX (Z32) problems

Other known issues

Critical Twin-Turbo System (VG30DETT Only)

Turbocharger Wear

Excessive turbo whine, metallic grinding or rattling from the turbos, blue smoke under boost (oil passing through worn seals), or reduced boost pressure.

Critical Twin-Turbo System (VG30DETT Only)

Power Steering Line Fire Risk

Power steering fluid leaks onto the hot exhaust manifold or turbo housing. In extreme cases, the fluid ignites.

Minor Engine -- VG30DE/DETT (All Models)

Timing Belt Failure Risk

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.

Common Engine -- VG30DE/DETT (All Models)

Spark Plug Access (Rear Bank)

The rear three spark plugs become fouled, worn, or fail, causing misfires, rough running, and reduced power.

Critical Engine -- VG30DE/DETT (All Models)

Oil Leaks

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.

Minor Engine -- VG30DE/DETT (All Models)

Overheating

Temperature gauge climbs, particularly in traffic or on hot days. Coolant loss. Steam from under the bonnet.

View all 15 300ZX (Z32) problems