Tires and Automotive Services, Whittier, Santa Fe Springs CA

	12200 E. Washington Blvd. Site A Whittier CA 90606 (562) 945 - 2658	Owners: Maritza and Gilbert Hernandez I Our Shop I Contact Us I

ENGINE OILS AND COOLING SYSTEM

For most people their motorcycle, car or jeep is a major investment as well as being a means of transportation. To minimize the repair costs and ensure reliability of the vehicle, it is important to use good quality oils and filters, carryout maintenance at regular intervals, use proper fuel and keep the engine from overheating.

FUNCTION OF ENGINE OILS

The topic today is about the function of engine oil and the various qualities of engine oil. To understand the importance of engine oil for the engine, whether it is a Suzuki Alto or the Khalid Main Battle Tank, it is necessary to know the various functions of oil. These are:

1.	Lubrication - of the many moving parts.
2.	Cooling - especially of the pistons ( the temperature of the combustion chamber gases can go up to 2400ºC ).
3.	Cleaning - oil helps keep the engine parts clean. The blacker the oil, the better the oil is doing its job. Some people think if the oil becomes black quickly the oil is not of a good quality. Whereas the correct picture is that this oil is doing its job.
4.	Gas Sealing - during the combustion process very high pressures are developed. Oil helps the piston rings to seal these pressures.
5.	Anticorrosion - the diesel fuel available in Pakistan contains about 1% Sulphur. While the engine is working, through chemical reactions this Sulphur becomes Sulphuric Acid ( please refer to your Chemistry text book for the chemical equations ). This acid then corrodes the internal parts of the engine. This is why engine manufacturers recommend that the oil change interval be reduced. Owners having petrol or CNG engine driven vehicles need not worry on this account.
6.	Antiwear - a good quality oil will minimize wear.

SELECTION OF ENGINE OIL VISCOSITY

Engine oil is available from the Petrol Pumps in different viscosity's, namely SAE 40, SAE 50, SAE 15W-40 and SAE 20W-50. If you were living in Canada, where in most parts of the country temperature goes down to -40ºC in the winters, you could buy
5W-30W engine oil. For those not familiar with Viscosity's, basically the smaller the SAE NO. i.e. SAE 10 the easier it is for the oil to flow and the higher the SAE NO. i.e. SAE 50, the slower the flow of oil. Or in other words SAE 10 is a " thin " oil and SAE 50 would be considered a " thick " oil. You would use SAE 10 where the ambient temperatures remain below 10ºC and you would use SAE 40 or 50 where the ambient temperatures are in the range of 10ºC to 45ºC. But since SAE10 is generally not available at Petrol pumps people tend to use SAE 40. During wintertime this oil makes it harder to start the engine. You might have seen truck drivers put hot water in the radiator or light a small fire under the engine so as to make the oil thinner, and therefore easier to start the engine.

To overcome this problem using multi viscosity oils i.e. SAE15W-40, SAE 20W-50 would be a better alternative. During winter this oil acts as a thin oil and during the summer it acts as a thick oil. One immediate benefit you will notice if you change from SAE 40 to SAE 15W-40, is that in cold weather the engine starts much more easier. In addition internal lubrication of the engine is better and the life of the starter would be longer.

SELECTION OF OIL

It is important to select the most suitable oil for your engine. The thing to know is that all oils start as base oils. " The lubricating oil base stocks are then blended to various viscosity's. Additives are introduced into the oil to make it flow more freely at low temperatures, to protect engine parts from rust and corrosion, and to give the oil special properties to adapt it to its special use."

The number of additives in an oil determines its classification as to its quality ( and therefore price ). For diesel engine oil the classification is as below:

1.	CA -	This is considered the lowest class of oil.
2.	CB -	This is a little better than CA.
3.	CC -	This is a class higher than CB. This is the class of oil that is mostly used by Government organizations in their Vehicles. The thinking is to save on cost. Whereas in the long run it results in premature failure of the engine and extra cost to overhaul the engine.
4.	CD -	This is a higher class of oil. For owners of vehicles with turbo charged engines, this is the least costly class of oil that can be used by them. A turbocharger is essentially an air pump providing greater volume of air to the engine. Since it rotates at RPMs ( Revolutions Per Minute ) of 50,000 to 100,000, use of CD Class oil is recommended.
5.	CE -	This is a class better than CD Class.
6.	CF-4	This oil is step higher than CE Class
7.	CG-4	This oil is the next to best class of oil available in the local market.
8.	CH-4	This is the highest quality of oil presently available from Petrol Pumps and Auto Parts stores.

One of the oil companies is in the process of introducing CI-4 Class oil. But this should be used only in engines of brand new vehicles

If used in old engines oil consumption can be a problem.

Petrol engine oils have a similar rating starting with SA, SB, SC, SD,SE, SF,SG, SH with the top rating of SJ. SJ class would be the best and most expensive oil.

Now you must be wondering how you can determine the Class of oil. All well-known oil Companies specify the Class on the oilcan. If you read the label it says " API SERVICE CG-4/SF ". Also the higher the class of oil the more expensive the oil.

Now a word of caution. It is advisable to buy the engine oil from a Petrol Pump you Trust. Though the Oil Companies are selling the oil in cans that are pilfer-proof and shrink wrapped ( covered in thin plastic sheet ), there are smart crooks who can make you think you are buying the genuine article.

You may now be wondering what benefit it is to use a better quality oil ( and more expensive oil ) over a lower quality oil ( and cheaper oil ). Most mechanics will tell you to change the engine oil every 2000 to 2500 Kms. This would be correct if you were using a CD class oil. In case you use a CG-4 class oil you can extend the change interval to 5000 Kms. If you calculate the cost of oil per kilometer, it would be less for the CG-4 class. Also you would save by not having to change the engine oil filter. Plus the engine would run better and longer, saving you much money in the long term. At this time I would like to mention that I change the engine oil ( I have been using CF-4 and CG- 4 Class oils ) every 5000 Kms in the Land Cruiser provided by my Company. This vehicle has done over 225,000 Kms and the only thing I have done to the engine is to check and adjust the valve clearances, which is considered as part of scheduled preventive maintenance.

Before running out and buying the most expensive engine oil for your vehicle, you should be aware of the condition of vehicle's engine. If you are using a single viscosity oil, i.e. SAE 40 is the norm and change to a multi-viscosity oil with a higher Class rating, you may find that your engine is consuming more oil than before. This is because your engine is weak ( due to wear ) and in need of an overhaul. Therefore you would be better off sticking to the previous oil, in case your pocket book doesn't allow you to do so.

COOLING SYSTEM

Some of you must be thinking why I am talking about the cooling system when the main article is about the engine oil. Just remember that when the engine oil temperature exceeds 120ºC, an increase of only a further 10ºC will cause the oil to deteriorate by over 50%. When the cooling system is not cooling effectively the water temperature will rise, directly causing an increase in engine oil temperature.

The optimum engine water temperature is between 70ºC to 95ºC for cars, jeeps, pickups and other small vehicles. If your water temperature gauge does not move it means that the thermostat ( it helps maintain the engine temperature in the optimum range ) has been removed or is stuck in the open position. To remove the thermostat from the engine when it is brand new, is almost as bad a person taking a blood transfusion tainted with HIV. When engines run cold ( below 70ºC ) the piston rings do not expand completely, water that is produced during the combustion process mixes with the engine oil ( affecting the oil's lubricating qualities ), in diesel engines the Sulphur in the fuel reacts with the water ending up in Sulfuric Acid. In other words do not allow your mechanic to remove the thermostat, because by doing so he is damaging your engine and causing it's premature overhaul.

The other important parts of the cooling system is the radiator which must be kept clean externally as well as internally. The best way to keep the radiator and cylinder block clean internally, is to use a coolant ( but in the correct proportion ). The radiator cap is also very important. When properly functioning it allows the hot water in the radiator to go to the plastic bottle connected to the radiator and when the water in the radiator and cylinder block cools, it draws water back into the radiator. If you are having to add water in your radiator every day, and there are no visible water leaks, then your radiator cap is the culprit. When buying a new radiator cap make sure it is of a good quality otherwise you are wasting your money. Sometime you will find that the fan belt has become worn or hard. In this case the fan is not rotated fast enough due to belt slippage causing the water temperature to rise.

Engine timing whether a diesel, petrol or CNG engine, can cause overheating if the timing is incorrect. Similarly if the brake cylinders get jammed, and shoes/ discs rub against the brake drums or brake discs, the water temperature will rise. Please note that I do not intend to alarm too much. However remember a little care for your car will give you many kms and years of trouble free service.

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