Repairing Car

What Engine Oil?

Engine Oil companies provide information as it relates to the “typical data inspection sheet”.
This basic information is an average of the physical and common chemical properties that are contained in their prospective engine oil blend’s.

In all actuality the most important ingredients or properties for the consumer is the zinc%, sulfated%, flash point, pour point and most commonly advertised or talked about: viscosity and viscosity index.

Viscosity, technically put is the resistance to flow and its ability to maintain sheering stress which is dependent on flow. Many engine oils are pretty thick and allow for higher viscosity and the thinner oils allow for less viscosity.

Why have the variable levels of viscosity, and not just maybe 1 or 2 .. ??..and more importantly what's in it for me and my vehicle??

One of the most important ingredients to the operation of an engine is the Oil and its ability to lubricate at various loads and temperatures. If the oil has too high a viscosity rating, it will lose its ability to pump throughout the engine at lower temperatures and the “film” may tear at higher rpms. While engine oil lube with too low of viscosity may shear and loose “film” strength at higher temperatures.

With multi-viscosity oils, polymers are added to a light base which will prevent the oil from thinning as much when an engine starts to warm up and attain its operating temperature. A great simple way of looking at the multi-viscosity oils is actually to think of 10W-50 as 50 weight oil that would not get any thinner than a 10 Weight oil when hot or at its operating engine temperature.

The key with polymers in engine oil (which have over the years proved to be very effective and a huge improvement in engine oil technology), is to keep the narrowest range of viscosity that is appropriate for the type of climate and seasons that you encounter. So take the winter temperatures and the lowest it may reach and do the same for temperatures at their highest peak for the summer season. Generally speaking, the Arizona low lying areas that experience hot summers and mild winters typically engage a 5w20 engine oil, BUT, the rule of thumb is to ALWAYS CONSULT WITH YOUR VEHICLES OWNERS MANUAL. There is a lot of misinformation about engine oil being divulged at some lube shops, and it is highly recommended to demand what is stated in your vehicles owners manual.

Viscosity Index is a number that indicates the rate of change of a specific oil during a various temperature ranges, The higher the number the lower rate of change and the lower the number the higher rate of change. THE HIGHER NUMBER is typically the better one to go with,as this allows for smoother operation of engine bearings and moving parts.

Of all the advancements in oil technology Synthetics offer significant differences, since their chemistry is designed for higher temperature oxidation resistance and lower tendency to form deposits in an engine.

Now, the DRAIN interval AND timeline of when you change your oil is absolutely one of the most important things that you can do to extend the life of your engine as it was originally designed for by the engineers. When you have a driving cycle that is: engine at normal operating engine temperature driving mainly freeway, and dust free environments, you can expect to replace the engine oil at 7500 miles…HOWEVER, most driving cycles are this: Stop and go traffic, city driving, trips of less than 10 miles or extreme heat or cold, which has now put you driving cycle at THE SEVERE SERVICE category….are one of these severe service drivers ?… It makes a big difference in the long run, as to what you will pay in avoidable auto service\repair costs if you get these two service definitions confused. QUALIFY NOW, AS TO WHICH DRIVING CYCLES YOU PERFORM….SEVERE SERVICE OR NORMAL SERVICE.

You can with synthetic oils run your engine beyond the service intervals a lot better than conventional oil, as they do not react to combustion and combustion byproducts to the extent of the “ older designed “ engine oils. THIS IS NO excuse. Always check your owners manual for specifics, and ALWAYS STAY TIMELY WHEN YOUR ENGINE OIL NEEDS TO BE REPLACED...


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