Motoring queries from readers are answered every week by MICHAELMcALEER
From Mary O'Sullivan, Dublin:
A few months ago I heard a slight noise in our 13-month-old Opel Astra Coupé. I brought it to the garage and they told me that the turbo needed to be replaced and, given how unusual this is, Opel would replace it free of charge.
Opel is to be commended for this level of customer service which reassured a worried customer. However a few days later I put up the sun visor and spotted a little label in the right hand corner of the windscreen telling me to let the engine idle before turning it off. As you can imagine, this label surprised me.
I spoke to a gentleman in the services department who told me that, yes, the engine should be run idle for 60 seconds. It's necessary for all turbo cars, he said. Has anyone ever heard of this rule?
THIS rule applies to all cars with turbos. You're not the first to think it applied only to diesels. In normal engines, oil in the sump can reach temperatures of 115°C to 130°C on long runs. If you switch the engine off immediately, some oil will vaporise, given the lack of air passing through. Over time this will damage the exhaust valves etc.
With a turbo, it can be operating red-hot at 30,000-40,000 rpm and reaching about 1,500°C. With such high revs, turbo bearings are very important. If the engine is switched off at this temperature, the oil on the bearings vaporises.
So, next morning when you start your car, the bearings will scrape. The advice is to let your car run idle for five-to-10 seconds, particularly after a long run. Turning it off immediately after a long drive and then cold starting next morning can take about 5 per cent off the life of a turbo.
From Conor O'Sullivan:
Can you explain a frustrating fact about motorbike insurance? According to the Government, a rider on a provisional A licence can ride a bike of only 33bhp or less.
To achieve this power output a restrictor can be fitted. But when I mention to my insurance company that the power-to-weight ratio has changed on my bike due to having a restrictor fitted, they didn't want to know.
The reason, they said, was that the restrictor is not required by the insurance company, but by the Government.
So, no reduction can be based on the fact that the bike has a restrictor fitted.
Yet, if you buy a bike which has a factory-fitted restrictor (a particular type of Suzuki Bandit 600), the insurance company will accept the power-to-weight ratio and give you a break.
So, my 500cc bike with restrictor (which cost €260 to buy and fit) is group 8 insurance. Yet, a new bike with a bigger engine (Suzuki 600), but a factory-fitted restrictor, would be group 5.
A LOT seems to depend on which insurance company you are talking to and to whom you are talking. It's all too often the case that you can phone several times to the same company, speak to a different person each time and get different answers - and quotes.
John Wheeler tells us that, if a restrictor has been professionally fitted there should be a restrictor certificate, and usually that is acceptable. Most main dealers and/or makers of restrictor kits can organise this.
"Doubtless one reason some insurers are wary of 'restrictors' is that some types are very simple mechanical devices which can be removed in minutes," says John. "On one well-known, top-of-the-range machine it can be 'adjusted' with a spanner."
From Ken Caraher, Blessington
Where can I buy a Royal Enfield 65 as described in Motors on Novermber 27th? Are there any Irish dealers, north or south?
THE Irish dealer for Royal Enfield motorcyles is Shenans Garage, Waterford (051 880185). The bike will cost about €6,207 after importation.