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Nissan Patrol: TB42 petrol head gasket failure

TB42 petrol head gasket failure is a common engine fault on the Nissan Patrol on the 1987–1997 cars, and we rate it critical. Putting it right costs $2,200 to $4,500 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 48 documented faults on the Nissan Patrol.

Vehicle
Nissan Patrol
Engine
TB42
Years
1987–1997
Fuel
petrol
System
Engine

This page covers the Nissan Patrol as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Nissan Patrol faults48 documented faults on this model

What you are looking at

A removed multi-layer steel head gasket held up, showing staining around the cylinder bore.Example of the part — not this vehicle

A used multi-layer head gasket. Discolouration between a cylinder and a water gallery is the tell.

John Furman · CC BY-SA 3.0 · Wikimedia Commons

What goes wrong

The 4.2L TB42 petrol engine is prone to head gasket failure, particularly when coolant maintenance has been neglected or the engine has overheated. The cast-iron block and alloy head combination is susceptible to warping after overheating events. Once the gasket fails, combustion gases enter the coolant or oil, accelerating engine damage. A common pattern in NZ/AU Y60 Patrols with high mileage or unknown service history.

What you would notice

  • White smoke from exhaust on startup or under load
  • Coolant loss with no visible external leak
  • Milky or frothy oil on dipstick or oil cap
  • Overheating gauge readings climbing at highway speeds
  • Bubbling in coolant overflow reservoir

How to check it

Where to look. Top of engine — cylinder head gasket sealing surface between block and head

  1. Check oil filler cap and dipstick for white emulsion.

  2. Observe exhaust for sustained white smoke.

  3. Check coolant for oily film or bubbles.

  4. Request compression or leak-down test across all cylinders.

  5. If a workshop inspection is possible: Pressure-test the cooling system cold and inspect for pressure loss.

Parts involved: Head gasket.

What it costs to put right

$2,200 to $4,500 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

  • “Has the engine ever overheated? Has the temperature gauge ever gone into the red?”
  • “When were the coolant and thermostat last replaced?”
  • “Has the head gasket been replaced previously, and is there documentation?”
  • “Has a compression or leak-down test been done recently?”

Now check the Nissan Patrol you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Nissan Patrol buyer questions

Is tb42 petrol head gasket failure serious on a Nissan Patrol?

We rate it critical and common on the Nissan Patrol. The 4.2L TB42 petrol engine is prone to head gasket failure, particularly when coolant maintenance has been neglected or the engine has overheated. The cast-iron block and alloy head combination is susceptible to warping after overheating events. Once the gasket fails, combustion gases enter the coolant or oil, accelerating engine damage. A common pattern in NZ/AU Y60 Patrols with high mileage or unknown service history.

How much does it cost to fix on a Nissan Patrol?

$2,200 to $4,500 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Nissan Patrol years are affected?

Our research records this fault on the 1987–1997 Nissan Patrol. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Check oil filler cap and dipstick for white emulsion. Observe exhaust for sustained white smoke. Check coolant for oily film or bubbles. Request compression or leak-down test across all cylinders. If a workshop inspection is possible: Pressure-test the cooling system cold and inspect for pressure loss. Look here: Top of engine — cylinder head gasket sealing surface between block and head