2000GT

Rattling or slapping noise from the front of the engine, particularly on cold startup. In advanced cases, the cam timing shifts, reducing power and causing rough running.

The duplex timing chain that drives the twin overhead camshafts stretches over time, even on low-mileage engines, because the chain has been under tension for decades. The chain tensioner may also lose effectiveness as its spring weakens or its piston seal leaks.

Replace the timing chain, tensioner, and chain guides. This requires front cover removal and careful cam timing setup. On a 2000GT, this is a specialist job, the DOHC head requires precise cam timing to avoid valve-to-piston contact. Cost: $3,000-6,000 AUD at a specialist workshop.

Oil puddles under the car, oil residue on the engine and chassis, dropping oil level in the external oil tank. Potential oil starvation if leaks are severe.

The 3M's dry-sump system uses external oil lines, an external oil tank, and a separate scavenge pump, all with joints, seals, and fittings that deteriorate with age. Cars that sit for extended periods are particularly prone to oil line seal hardening and cracking.

Inspect all oil lines, fittings, and the oil tank for weeping or active leaks. Replace any hardened or cracked lines with correct-specification replacements. The oil tank itself can develop pinhole leaks from internal corrosion if old oil with moisture contamination has been left in it. Cost: $1,000-5,000 AUD depending on the extent of replacement needed.

Overheating, coolant loss, visible corrosion on radiator fins, reduced cooling efficiency.

The original aluminium crossflow radiator corrodes internally from age and coolant contamination. Dissimilar metals in the cooling system (aluminium radiator, iron block, brass fittings) create galvanic corrosion if the coolant is not maintained with the correct inhibitor package.

Re-core the original radiator with a new aluminium core (preserving the original tanks if possible for authenticity) or source a reproduction radiator from a specialist supplier. Always flush the entire cooling system and use fresh coolant with the correct aluminium-compatible corrosion inhibitors. Cost: $1,500-4,000 AUD for re-core or reproduction.

Coolant dripping from the water pump weep hole, low coolant level, overheating.

The water pump mechanical seal wears with age and use. On cars that sit for long periods, the seal dries out and loses its sealing surface.

Rebuild or replace the water pump. NOS pumps are virtually unobtainable; rebuilding with new seals and bearings is the standard approach. Cost: $800-2,000 AUD.