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Published on September 19, 2007

That was the story about the truck carrying natural gas, which was heading for the station as usual, when a pickup crashed into it at high speed. The fuel tank of the pickup cracked, and the fuel caught fire while the pickup was stuck under the natural-gas truck.

By the time officials and the fire brigade arrived at the scene, the body and tyres of the pickup were already well alight, and the fire had also spread to the body and tyres of the large truck. The fire burned for half an hour before the automatic safety system opened the valve and quickly released the natural gas from the container. After that the container exploded.

Thanks to the high pressure, the natural gas was released so quickly that it did not catch fire. It just disappeared into the atmosphere, and no major harm was done. If the truck had been carrying liquified petroleum gas (LPG), this would have surely turned into a major tragedy like the one on New Phetchaburi Road many years ago.

It is a pity that government agencies encouraging people to switch over from LPG to compressed natural gas (CNG) do not use the Phetchaburi tragedy as a tool to encourage the use of CNG. I don't know whose fault it is - the government agencies or the company that has been hired to do the public relations for CNG. Following my column asking motorists to turn off the engine while refuelling, I received a large number of responses, and this e-mail from TS is one of them.

 

Dear Khun Pattanadesh,

I admired your column about helping to create a much safer society. On some occasions I have seen petrol-station staff smoking cigarettes near the pumps - very scary!

I also read about one pickup truck with two "old" fuel tanks that exploded at a Bangchak station yesterday. What can we as a society do to prevent this kind of accident? Please don't ask me, as I have no authority or power to do anything.

Enough of this. Now I have questions about changing the engine oil for a car that is driven less than 5,000 kilometres per year. First, when is the right time to change engine oil? I am now using full synthetic motor oil, which claims 15,000km between oil changes is enough. Second, is the practice of changing engine oil just once a year a good habit?

Thanks very much and looking forward to your kind answer.

TS

Thanks for agreeing with me on safety, and I would also like to say right now we don't have to care who follows safe practices and who doesn't. Just make ourselves follow the safety rules and follow the traffic laws first. If we can do this, then Thai society will have a chance to improve. When I say we alone, it includes you and me and a lot of other people who have the same thinking. If we keep on making excuses - saying that others are not doing it, so why should we - no one will ever get it started.

Don't wait for those with authority to initiate this, because they are more concerned about keeping the authority for themselves and won't care about the rest of us. About the oil-change questions, let me sum things up as follows.

Usually you can drive the vehicle for the full distance before the oil change is recommended, regardless of the time. For example if you drive 5,000km per year - which is so little I wonder why you would want to spend the money on a car and then maintaining it - you can use it for two years before changing the engine oil.

However in reality, once the engine oil heats up and cools down, the changes in temperature could cause small water molecules to form in the oil. Although the amount of water is small, if you are unlucky this tiny amount of water may be sucked into the important lubrication areas in the engine, causing more wear than usual.

If you use the car as little as mentioned, the best way is to drain out a little engine oil from the bottom of the crank case. About a quarter to half a litre is enough. Since water is heavier than oil, if there is any water it will sink to the bottom of the crank case and be drained out as you release the nut. Then just add additional oil to the normal level. This way you won't have to change all the engine oil at once.

As you can see, cars that are driven infrequently have as many problems as those that are used heavily. Sometimes they have even more problems.

Pattanadesh Asasappakij

E-mail your motoring questions to

Pattanadesh@nationgroup.com.

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