However, if you detect a strong, almost sweet odour coming from your engine when the car is running, it could be a sign that your cylinder head is cracked. This slightly odd smell is a combination of coolant, which is normally tightly contained by the cylinder head, burning as it leaks from the cylinder. It’s Getting Hot in Here. Kubota cylinder heads are under warranty for 2 years from the date of purchase. V8 SBC SBF and BBC cylinder heads are under warranty for 6 months from the date of purchase. All other cylinder heads and parts, including crankshafts, head bolts, gaskets, pumps and valve trains, are under warranty for 1 year from the date of purchase.
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IntroductionFirst introduced in 1993, Toyota’s 1KZ-TE was a 3.0-litre turbo-dieselfour-cylinder engine. Key features of the 1KZ-TE included its alloy castiron block, aluminium alloy cylinder head, single overhead camshaft, twovalves per cylinder, drive-by-wire electronic throttle control and indirectinjection. Furthermore, the 1KZ-TE engine had a 4400 rpm redline.
ForAustralia, the 1KZ-TE engine was first introduced in the.For theand, in which the 1KZ-TEproduced 96 kW, the engine was fitted with an air-to-air intercooler. Crankshaft, connecting rods and pistonsThe 1KZ-TE engine had a fully balanced steel crankshaft that had fivejournals and operated on aluminium alloy bearings. The connectingrods were made from lightweight carbon steel and each rod had an internaloil passage which supplied an oil gallery in the piston. The small-endconnecting rod bearings were tapered to reduce mass, while the big-ends hadplastic region tightening bolts to maximise clamping force Thepistons were made from aluminium alloy and a FRM (fibre reinforced metal)top ring groove to improve wear resistance.
Balance shaftsThe 1KZ-TE engine had twin counter-rotating balance shafts within thecrankcase to cancel the secondary inertia forces that were inherent in anin-line four-cylinder engine. Since each piston reached its maximum speed –both rising and falling – at a point just above the centre of the stroke,the upward inertial force of the two rising pistons was greater than thedownward inertial force of the two falling pistons. To offset this, the twingear-driven balance shafts counter-rotated at twice the speed of thecrankshaft. Injection and combustionThe 1KZ-TE engine had electronically controlled, indirect fuel injection viafuel injection nozzles that had a double-cut needle. Fuel was supplied tothe injectors via a Denso ‘Generation 3’ (ECD-V3-Rom-D) vane-type fuel pumpwhich featured a spill control valve, timing control valve, fuel temperaturesensor, engine speed sensor and correction PROM (Programmable Read OnlyMemory). The 1KZ-TE engine had swirl type combustion chambers withceramic-tipped glow plugs. Furthermore, the 1KZ-TE engine had a compressionratio of 21.2:1; the firing order was 1-3-4-2.
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1KZ-TE: OverheatingOverheating of the 1KZ-TE engine requires urgent attention since it cancause the cylinder head to crack. Overheating may be caused by:. Failure of the viscous fan hub – this is generally noticed bytemperatures rising when ascending hills or during stop/start traffic onhot days;. Blockage of the radiator;. Seizure of the wastegate actuator resulting in overboost;. A hole in the heater hose; and,. Too much load on the cooling system – a worn torque converter maycontribute to this.Toimprove the cooling system, common modifications for the LandCruiser Pradoupgrading the radiator and fitting larger exhaust systems.
1KZ-TE: Cracked cylinder headAs a result of overheating, the 1KZ-TE is susceptible to cracked cylinderheads. Symptoms of a cracked cylinder head include:.
Small bubbles in coolant system, pushing coolant into the overflowbottle;. Consumption and discolouration of coolant;.
Rapid overheating;. Rough running; and,. A loss of power.If the cylinderhead has cracked, the turbocharger is susceptible to overheating – this maycause excessive movement of the shaft and allow the blades to hit thehousing. It is recommended that the cylinder head be replaced with a genuineToyota head since there have been reports of casting faults in non-genuineproducts. Please note that pressuretesting the cylinder head does not always reveal a problem.
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