Cars

[giraffe_02]

Hi I would like to know a couple of things about cars: 1 what does the head gaskett do? 2 You know the oil you put in the engine, where does it go once it has gone round the engine? because you have to top it up Could make your answers easy to understand as I am female and no nothing about cars!!!

[Ethel]

http://en.wikipedia.org/wiki/Head_gasket


A certain amount of oil will 'evaporate' but you shouldn't have be topping up it too often. If you are, you are losing oil because something is wrong.

[qapmoc]

Ummm, I think that oil takes a few years to vaporate. what actually happens in a internal combustion engine is that some traces of oil remain on the cylinder walls by design to lubricate the piston rings and this oil gets burnt up during combustion. That said, normally you should not need to top up between oil changes unless the engine is worn out or if there is an oil leak.

The oil in the engine circulates continously around all parts of the engine to lubricate and cool it and is reused over and over again, the reason you have to change the oil every X miles is because the oil collects dirt and carbon particles and eventually loses its lubrication properies.

[qapmoc]

oops evaporate not vaporate

[clancyblob]

The "head gasket" is a special seal that goes between the engine and the cylinder head (the sort of lid of the engine that keeps the explosions in). The spark plugs and valves go through this lid to set the explosions off. There are little passages drilled through all these parts so water can flow round to keep the engine cool. If the head gasket leaks, as it may after many miles, water will seep into places in the engine where it shouldn't be. Also oil that keeps the moving parts nice and slippery will ooze out making the engine oily on the outside (which may be why the oil level goes down). The gasket is cheap, but the engine needs to be taken to bits to get to it, which takes hours, and is why it costs money for a garage to replace it.

A car can need it's oil topping up because: 1) it is leaking out somewhere - look on the drive for those nasty black patches: 2) the engine is worn, so oil keeping things slippery is getting into where the explosions are. The oil burns in the explosions giving bluey smoke out of the exhaust: 3) The head gasket has gone (got a crack in it) allowing oil to be pushed out of the engine coating it in black stickiness.