Toyota Hilux: 3RZ-FE / 2RZ-FE cast-iron exhaust manifold cracking between the centre runners

The cast-iron exhaust manifold on the 2.0 2RZ-FE and 2.7 3RZ-FE petrol engines cracks, almost always between the middle two runners over cylinders 2 and 3. Heat cycling plus the weight of the exhaust hanging off it does the damage, and sagging or broken engine mounts make it far worse because the manifold ends up carrying the pipe. It starts as a tick or puffing noise on cold start that fades as the metal expands and closes the gap, then becomes a permanent exhaust roar. Beyond the noise it upsets the oxygen sensor reading, so the engine runs richer than it should and fuel use climbs. It is common enough that Toyota's later 1998-on 'mini header' manifold is the standard replacement part, and the original design cracks again if one is refitted.

• Ticking or puffing from the engine bay on a cold start that quietens as it warms
• Exhaust noise that has got louder over time
• Smell of exhaust in the cabin at idle or with the windows down
• Check-engine light for a lean mixture or oxygen sensor fault
• Fuel use higher than it used to be

Stand beside the engine bay at a cold start with the bonnet up and listen for a rapid ticking or puffing in time with the engine - it is loudest in the first minute and fades as the manifold heats up and the crack closes. Have someone hold the revs at around 2,000 rpm and listen again from the passenger side, which is where the manifold sits. Shine a torch down the back of the engine at the manifold and look for a black sooty streak on the casting or on the heat shield, which is exhaust escaping and staining the metal. Push down firmly on the top of the engine while it idles and see whether it rocks more than a little, because tired mounts are what breaks these manifolds. Ask whether the manifold has been replaced already and whether the later part was used.

Parts involved: Exhaust manifold.

$700 to $1,800 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.

• “Has the exhaust manifold been replaced, and was it the later 'mini header' type?”
• “Does it tick or puff for the first minute when cold?”
• “Have the engine mounts ever been replaced?”

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

• TTORA forum thread: 'Identifying the infamous Cracked Exhaust Manifold?'
• TacomaWorld forum thread: '3rz exhaust manifold, Y-pipe leak [FIX]'
• CustomTacos forum thread: 'Cracked exhaust manifold'
• Pirate4x4 forum thread: '2.7 3RZ mini-header confusion' - post-1998 manifold used as the standard replacement