R Sweeney wrote:
> "y_p_w" <y_p_w DeleteThis @hotmail.com> wrote in message
> news:w5QAf.933$1n4.582@newsread2.news.pas.earthlink.net...
>
>>
>>R Sweeney wrote:
>>
>>
>>><mulder DeleteThis @x.files> wrote in message
>>>
>>>
>>>
>>>
>>>>Not unless you have access to the previous service records. But, it
>>>>doesn't really matter since you will be draining that oil out anyway,
>>>>and all you need to do is use the correct viscosity for the expected
>>>>ambient temperatures as called for in the manual. What was used before
>>>>isn't important.
>>
>>Anywhere from 80-90% of the oil is being drained out anyways.
>>There's very little that can go wrong simply because the type
>>or weight of oil is changed. Most cars are very tolerant of
>>different oils. What's available 7 years from now isn't going
>>to be like what's available today.
>>
>>
>>>Or you just use synthetic that holds a more constant viscosity
>>>regardless of temperature.
>>
>>I don't know if that's a good way of describing it. Nothing
>>holds a "constant" viscosity. Virtually all fluids thin out
>>with an increase in temperature and thicken when colder. I've
>>heard swimmers describe freezing water as "viscous".
>
>
> try changing oil outside in January
> try cranking on a sub-zero degree day
>
> the synthetics flow just as they do in summer
> but the naturals "flow" like cold maple syrup
There's nothing "natural" about any modern motor oil. They
all use polymeric VI improvers, pour point depressants,
detergents, dispersants, and any number of man-made chemicals.
In many ways, the terms "synthetic" and "conventional" are
marketing terms. Mobil checmists originally wanted to call
their product a "synthesized hydrocarbon", and sold their
first Mobil 1 offering as "Mobil SHC".
Even in cold temperatures, a 20W-50 "synthetic" oil will
flow out of the bottle slower than a "conventional" 5W-20.
The advantage of many synthetic oils is that they don't
contain waxes that tend to thicken in cold temps. Oil
processing has removed a lot of conventional oils and
pour point depressants help resist wax crystallization.
> Nothing holds a constant viscosity vs temperature, but
> synthetics come pretty darned close over normal North
> American temps.
Depends on the "synthetic" oil. Many "synthetic" oils
these days are primarily group III base oil. Some companies
market products based on group III as "conventional". They
certain do outperform oils made even a few years ago.
Many conventional oils have quite acceptable cold weather
performance.
Now - I'm not knocking synthetic oil. I live in a temperate
climate but use Mobil 1 5W-30. It certainly is a good choice
to withstand the stresses from a turbocharged engine.
>> Stay informed about: oil question. .forester