Checking the level of your car engine oil is something you should do regularly. It is very easy to do, and regular checks can save you huge amounts of money. How often you check your oil level is dependant on the use of your vehicle, but a weekly check would be a good average for most people. Even if you do check your oil on a regular basis, it's also worth while checking it again before you go on a long trip. Safe is always better than sorry.
Always check your oil when the engine is cold, or at least half an hour after it last ran. This is to ensure that all oil has descended to the sump and that your level check is as accurate as possible. Also make sure the vehicle is parked on a level surface.
The oil in your engine is as important to your car as is the blood in your veins. Without it, the engine will not run and if the level is low, then wear in the engine is increasing which means the life of individual parts in the engine is being shortened dramatically. In addition, low oil levels will mean the engine is running at a higher temperature than it is designed for. This could lead to other mechanical problems due to the heat, and your gas mileage will also suffer.
Many cars on the road today have long service intervals due to the efficiencies of their engines. This does not mean that you should not check the oil on a regular basis. Leaks within the oil system, due to vibration or the failure of service items such as the oil filter mean that the oil level can drop between these extended service intervals and no one would notice unless the level of the oil is checked on a regular basis.
A sudden drop in oil level can also point to a serious problem such as the start of an engine head gasket failure. This is because the oil and water pathways within the cylinder head have become compromised and the liquids mix. A sudden raise in oil level can indicate this too. If this symptom is noticed while checking the oil, take off the oil filler cap and have a look at the inside of the cap. If there is a white substance that looks like mayonnaise it means water is getting into the oil, again pointing towards a head gasket failure.
Another reason for a dramatic drop in oil levels is pertinant to diesel vehicles fitted with an intercooler or turbo. If a break in the oil channels occurs at a point where the oil gets into the engine, the engine will burn the oil and the turbo will have a sucking effect on the oil supply and deplete it very quickly. Again, this may not be noticed unless oil levels are checked on a regular basis.
Do not trust your oil warning light. These sometimes fail, but there is nothing to tell you that it has failed. It's an emergency system not something there to tell you to check the oil. There is nothing better than a physical check on your oil level and regular checks will keep your car running at it's optimum.