Jon_Bmw wrote:
Great put fully synthetic in a 130,000 mile beast, just watch it pour out and cause more harm because its so thin! The older a car gets, generally the more they leak, so trying to encourage this with very thin oil is generally not recommended, but if your BMW parts man said so, rush off and do it!
Oh how wrong you are
How is it that a synthetic oil is thinner?
Let me put you straight here before you get the wrong idea
A synthetic oil is ANY viscosity you want it to be. It's not the type of basestock (synthetic or petroleum) that determines the thickness of the oil, it is in fact the viscosity!
You can buy a mineral 10w-40, a modified mineral 10w-40 (semi-syn) or a fully synthetic (pao/ester) 10w-40 - They are all the same viscosity and have to meet API tests to prove the fact.
The difference is in the quality and basically synthetic is the best because it lasts longer and lubricates better.
Perhaps a few myths should be dispelled here
The Myths regarding Synthetic Oils
What are Synthetic Oils?
Synthetic Oils are fuel efficient, more fluid and resistant to thermal breakdown, they are constructed in laboratories using basestocks and special additive packages. They are specially formulated to meet and perform to standards set by API and ACEA as required by OEMÔš's.
Synthetic motor oils damage seals.
This is untrue. Why would lubricant manufacturers build products that are
incompatible with seals. The composition of seals present problems that all types of oils must overcome.
At the end of the day, it is the additive pack in the oil that counts. Additives are added control the swelling, shrinking and hardening of seals.
Synthetics are too thin.
This is untrue. In order for an oil to be classified in any SAE grade (0W-40, 5w-40,10W-40 etc) it has to meet guidelines with regard to viscosity or thickness.
For example, any oil with a viscosity of 10W-40 has to operate at -25 degrees centigrade and 100 degrees centigrade to pass these tests or it cannot be rated as a 10W-40.
Synthetics mean higher oil usage.
This is untrue. Synthetic motor oils are intended for use in mechanically sound engines, that don't leak oil. In these engines oil consumption will actually be lower because of the lower volatility of Synthetics. They also have better sealing capabilities between piston rings and cylinder walls. Synthetics also have better oxidation stability. (They resist reacting with oxygen at high temperatures)
Synthetic Oils are not compatible with other oils.
This is untrue. The synthesized hydrocarbons, polyalphaolefins, diesters and other materials from high quality basestocks are fully compatible with other oils.
It is best to stick to the same oil for topping up that you have in the engine. It is best not to mix oils, as additives are blended for specific oils. When different oils are mixed additive pack balances can be upset so for the best performance, itÔš's better not to mix them.
Synthetic Oils produce sludge.
This is untrue. It is a fact that they are more sludge resistant than other oils as they are better at resisting high temperatures and oxidation. Because Synthetic oils have higher flash points, they withstand evaporation better leaving less deposits.
Synthetic oils can't be used with catalytic converters.
This is untrue. There is no difference between synthetic and other oils with regards to the components. Neither will damage catalytic converters.
Synthetic oils can void warranties.
This is untrue. No major manufacturers specifically ban the use of synthetic oils. More and more new performance cars are factory filled with Synthetic oils.
Vehicle warranties are based upon the use of oils meeting specific API Service Classifications and recommended viscosities.
Synthetic oils will last forever.
This is untrue. There are some people that believe that synthetic basestocks themselves can be used forever. However, it is a well known fact that eventually the additives will break down and cause the oil to degrade. The additives in the oil are effectively Ԛ“used upԚâ€a by moisture, fuel dilution and acids. Regularly topping up the oil will help but sensible oil change periods are recommended.
Synthetic oils will protect an engine for far longer periods than non-synthetics.
Synthetic oils are too expensive.
This is untrue. It has been proven through testing that Synthetic oils do have longer drain periods and provide better fuel economy. Add this to reduced engine wear and better reliability then do the maths. They are in reality better value for money than other oils.
Why do they cost more? It's no gimmick, they are better!
Cheers
Simon