Option — Shōwa Car Tuning & Buyers Guide (2000 Edition)

Inside an engine, metal parts such as the camshaft, pistons, crankshaft, and connecting rods are moving around. If the metal surfaces rub directly against each other, friction heat can make them seize. Engine oil lubricates the parts and prevents this. Engine oil also absorbs dirt, and it gradually wears out as you drive (though of course it doesn't deteriorate all at once). So you need to check its condition regularly; otherwise it may become badly degraded without you noticing, the oil film may fail...

To check it, pull out the dipstick on the side of the engine and inspect the level and condition. Engine oil is usually clear when new. It gradually gets dirty and dark, eventually turning black. By then, oil that was initially thick and slippery should have lost viscosity and become watery. At that point, it should definitely be changed. These days, auto-parts shops often offer free labor when you join their oil-service program, making changes easy. Still, it's not a bad idea to try changing the oil yourself. You'll feel that you're properly maintaining your car, and working on it yourself can make you more attached to it. If you can do this much on your own, you'll be a proper privateer from that day on.

GT-Rs and similar cars may risk oil-film failure. Even a winter grade suitable for around 2,000 cc may work. The GT-R in the GT Championship also uses this grade. It is thick, so small cars may be difficult to start. Most naturally aspirated engines are fine with this grade. Many naturally aspirated race cars use it too. Naturally aspirated engines generally produce less heat than turbo engines, so a lower viscosity is preferable. Honda engines are precisely built with tight internal clearances, so a slightly thinner oil may work well. For NSX VTEC models, 10W-40 is said to help the variable valve-timing mechanism operate better.