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Claims that contaminated diesel in New Zealand is fouling engines lack substance, the Motor Trade Association (MTA) says.
The MTA, which represents over 80 percent of New Zealand's service station owners and operators, has carried out a survey of 30 specialist diesel mechanics. It indicated there was no real increase in reported problems over the past three years, despite an increasing number of diesel vehicles on the roads.
The survey was in response to reports last month about growing concern a diesel bug, water and dirt could be damaging and destroying newer diesels.
MTA marketing and communications general manager Ian Stronach said the feedback from members confirmed that there had been no real increase in the number of reported contamination cases over the last three years.
"We are surprised and at a loss as to why some people in the industry have made these claims, as based on what members from across the country are telling us, there simply isn't any evidence to suggest that there is an issue," he said.
The number of diesel passenger cars, trucks and buses in New Zealand now accounts for 18 percent of the national fleet, increasing to 615,000 at the end of 2008, from 360,000 in 1999.
The dramatic surge in numbers should have led to an increase in the number of incidents.
"However, in this case, our analysis shows that the number of incidents have decreased in proportion to the number of diesel vehicles on the road."
Last month, the editor of the car buyers' guide, The Dog & Lemon Guide, warned motorists against buying diesel vehicles - unless they really had to.
Clive Matthew-Wilson said oil companies have admitted the problem through confidential payouts.
"We know that they have made a number of substantial settlements with very angry people, who have spent up to $30,000 getting their engines rebuilt," he told 3News.
"Don't touch diesel vehicles unless you're a commercial operator and doing at least 15,000km - but preferably 25,000km - a year," Mr Matthew-Wilson said.
AA technical advice manager Jack Biddle agreed that diesels were better for trucks and longer distance trips.
Mr Biddle said problems with contaminated fuel, both diesel and petrol, were not new, and would probably continue in future.
Newer, cleaner diesel engines, with higher pressure fuel and more precise requirements, were more susceptible to contamination, he said.
"There's nothing wrong with the engines, there's nothing wrong with the fuel, but the housekeeping of the fuel has become more and more important."
The MTA said there were several practical steps that vehicle owners could take to minimise diesel contamination.
If your diesel vehicle is not used frequently, keep the tank topped up to reduce condensation.
* Avoid filling from low volume containers.
* Get your vehicle serviced regularly.
* Pay particular attention to fuel filters and change them regularly.
* Get your vehicle checked immediately if the engine starts to cut out, particularly if you have only just filled your tank.
* Consider sticking to one service station so you are more able to prove the source of your fuel if it is found to be contaminated.
* Keep fuel receipts as proof of purchase if any problems occur.