Oil Specification

[Poppy]

There's a wealth of information here for any who may be unsure what to use, there are so many different suppliers out there .   http://www.driverstechnology.co.uk/oils.htm

The manual for your engine should also quote required ( preferred ) 'numbers and letters', which you should match to the 'letters and numbers' on the container of oil you buy. If you don't have a manual, you may well find the information on line.
 

 

 

[Vaughan]

That is very good advice.

For me, it is all about viscosity. An oil must be able to retain its substance and not get too thin, especially when running at high temperature. This is why some older diesels such as Perkins and BMC had an oil cooler, which was not necessary on the Broads, due to the very slow running speeds.

Remember Castrol GTX? They called it "Liquid engineering" and this could not be more true. The bearing journals and the pistons in your engine do not meet - they are separated by a film of oil, on which they run. If you ever get metal-to-metal contact on a bearing, then it overheats and seizes up.

This is especially true of a turbo charger, which rotates so fast that the fan axle actually floats on the oil, so the oil you choose must be suitable for a turbo.

So even if you do not use your engine a lot, the oil will still lose its viscosity over time. Change your oil regularly!