Radiator and Head-Gasket Claim: Testing Point-of-Sale Causation

BACKGROUND

A finance provider requested independent technical assistance concerning a vehicle in which a radiator failure and alleged cylinder-head-gasket failure had been reported.

The customer’s repairer maintained that the radiator had been defective when the vehicle was supplied and that this had caused the engine to overheat, resulting in consequential head-gasket failure.

The vehicle had completed a substantial mileage following purchase before the reported engine and cooling-system concerns arose.

The central issue was whether there was sufficient technical evidence to establish that the radiator was defective at the point of sale and whether that defect had directly caused the alleged head-gasket failure.

The repairer’s diagnosis stated that the head-gasket problem resulted from overheating caused by a cracked radiator. However, alternative causes and the possibility of reverse causation had not been properly considered.

A developing head-gasket breach can introduce combustion pressure into the cooling system. This can cause over-pressurisation and may contribute to radiator or cooling-system failure. It was therefore not technically safe to assume that the radiator had failed first.

We reviewed:

• The repairer’s written diagnostic opinion.

• The available complaint and repair chronology.

• The reported mileage and period of vehicle use following purchase.

• The warranty provider’s earlier assessment of the radiator failure.

• The information supplied concerning the alleged overheating and head-gasket failure.

No independent physical inspection report, pressure-test results, combustion-gas test results, cooling-system data, photographs, strip-down evidence or retained components were available.

We carried out an independent desktop technical assessment of the available evidence.

Our review considered the possible causes of radiator failure, including age-related deterioration, corrosion, impact damage, restricted coolant flow, thermostat failure, cooling-fan failure, water-pump failure, poor previous repair and cooling-system over-pressurisation.

We also considered alternative causes of head-gasket failure, including coolant loss, overheating, continued vehicle use following a warning, cylinder-head distortion, previous overheating events, internal deterioration and combustion pressure entering the cooling system.

We identified the testing and inspection evidence that would be required before reliable conclusions could be reached regarding causation, chronology and point-of-sale condition.

FINDINGS

The repairer’s assertion was not supported by sufficient technical evidence to establish that the radiator defect existed or was developing when the vehicle was supplied.

A serious head-gasket defect present at the point of sale would generally be expected to produce symptoms such as repeated coolant loss, overheating, misfiring, cooling-system pressurisation, poor running, exhaust smoke or temperature warnings. The substantial subsequent vehicle use was therefore relevant when considering whether the alleged defect had been present from the outset.

The warranty provider’s classification of the radiator failure as progressive deterioration did not itself establish dealer liability.

On the evidence available, the order of failure could not be reliably determined. It remained possible that radiator failure caused overheating, but it was also possible that a developing head-gasket problem caused cooling-system over-pressurisation and contributed to the radiator failure.

There was insufficient evidence to establish, on the balance of probabilities, that either defect had been present or developing at the point of sale.

We carried out an independent desktop technical assessment of the available evidence.

Our review considered the possible causes of radiator failure, including age-related deterioration, corrosion, impact damage, restricted coolant flow, thermostat failure, cooling-fan failure, water-pump failure, poor previous repair and cooling-system over-pressurisation.

We also considered alternative causes of head-gasket failure, including coolant loss, overheating, continued vehicle use following a warning, cylinder-head distortion, previous overheating events, internal deterioration and combustion pressure entering the cooling system.

We identified the testing and inspection evidence that would be required before reliable conclusions could be reached regarding causation, chronology and point-of-sale condition.

FINDINGS

The repairer’s assertion was not supported by sufficient technical evidence to establish that the radiator defect existed or was developing when the vehicle was supplied.

A serious head-gasket defect present at the point of sale would generally be expected to produce symptoms such as repeated coolant loss, overheating, misfiring, cooling-system pressurisation, poor running, exhaust smoke or temperature warnings. The substantial subsequent vehicle use was therefore relevant when considering whether the alleged defect had been present from the outset.

The warranty provider’s classification of the radiator failure as progressive deterioration did not itself establish dealer liability.

On the evidence available, the order of failure could not be reliably determined. It remained possible that radiator failure caused overheating, but it was also possible that a developing head-gasket problem caused cooling-system over-pressurisation and contributed to the radiator failure.

There was insufficient evidence to establish, on the balance of probabilities, that either defect had been present or developing at the point of sale.