A man who bought a Holden V8 but found the engine noise too loud has won the right to a full refund.
Anthony Wilson bought the 2015 Holden Commodore VF2 SS-V Redline 6.2L from Value Motors Lower Hutt in June last year.
But he found the engine made a noise, described as a "guttural knock", most noticeable for about five minutes until the car's engine warmed up. He did not hear the noise during his test drive, which he blamed on the engine already being warm.
Value Motors consulted experts and was advised that the noise was normal for the car, but Wilson disagreed - saying he had owned several similar Holdens in the past, and none had made the noise of the current vehicle.
There was no indication that the noise affected the car's performance.
Wilson rejected the car, having driven about 1200km, and asked the Motor Vehicle Disputes Tribunal to order Value Motors to give him a full refund.
In its January 17 decision the tribunal's found in Wilson's favour, ordering Value Motors to refund the $47,995 purchase price.
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Value Motors consulted Holden agent Brendan Foot Supersite about the noise complaint. The agent confirmed a "knocking type noise" could be heard when starting the car from cold and revving it lightly but said the vehicle was "okay".
It sent a recording of the sound to Holden New Zealand, which also advised the noise was "a normal characteristic of this engine" and nothing needed fixing.
But Wilson took advice from Marc Mulholland, director of Llama Engineering, who had experience with General Motors LS series engines such as his.
Mulholland assessed the engine as having "a high level of piston slap, with one extremely loud piston" on a cold start.
In drive, and with the engine slightly loaded, it was "unacceptably loud", Mulholland reported.
He advised Wilson not to drive the car.
He said the piston slap was not within "acceptable" realms and was damaging the engine.
Mulholland spoke at the hearing in support of Wilson's case. He said older LS engines were well known for having noisy pistons on starting but Wilson's engine was far noisier than would be expected in a vehicle of this age and mileage.
He believed the noisy piston may have partly collapsed.
Fixing the problem would require completely dismantling and rebuilding the engine, at a cost ranging from $6500-$11,247, he said.
Value Motors' expert at the hearing, automotive engineer Karl Pemberton, said piston slap on this type of engine was "extremely common" and there was no evidence of mechanical failure.
The piston slap only occurred briefly and had no detrimental effect on performance, he said - though he acknowledged he had not examined the engine himself.
Mulholland "strongly disagreed" with Pemberton, saying the noise did indicate stress on the pistons, which was likely to affect the engine's longevity.
The tribunal's assessor, Mr Dixon, agreed he could hear piston slap, which was highly unusual and gave cause for concern.
Following further testing, adjudicator J S McHerron concluded the noise was not an "ordinary characteristic" of such engines.
McHerron preferred Mulholland's evidence to that of Brendan Foot Supersite and Pemberton, concluding the vehicle did not meet the standards of the acceptable quality guarantee in the Consumer Guarantees Act. A reasonable consumer would not regard the vehicle as being fit for purpose, McHerron said.
The adjudicator ordered Value Motors to refund the full $47,995 within 14 days after which Wilson must make the vehicle available for Value Motors to collect.