Not in Minis, no.

Yes and no. Clean oil of the specified grade, replaced at the correct
intervals is ample protection for any motor. Engines don't die because
the correct oil was used, they die from mistreatment, coolant failure
and air filter failures. No synthetic oil will prevent any of these.

Consid also that the Mini engine oil is also the gearbox oil. Mineral
engine oil is poor enough gearbox oil. Synthetic engine oil is even
worse and has a reputation for causing problems in Mini gearboxes.

there is a usually a chant of "NO" when synthetic oil and mini are mentioned
in the same sentence.

However, problems that are often blamed on the oil being synthetic is more
likely to be caused by the wrong viscosity of the oil - Synthetics are often
very 'runny' - not good for the gearbox...

TTFN,
Dave

hiya
NEVER in a classic Mini. but if you are going to use it in a BMW Bini use
fully synthetic oil plus a small amount of carbide powder it will run like a
dream.:-)

fragged

all fraggeds advise is used at you own risk, and he cannot be held
responsible.

Amsoil has a 20W50 oil and Mobil has a 15W50. There has long been an
argument that using synthetics in a Mini is bad because the gear box
will chop up the long chain molecules in the oil. There is absolutely
no proof of this and in fact there is little difference in synthetic
motor oil and synthetic gear oil. My understanding is that synthetic
gear oil is the same as synthetic motor oil except that the gear oil
has different additive package with less detergent.

There are a lot of stories about failures due to synthetic oils for
about any car ever made. These stories, including the two that recur
in this group are usually of the form, " I tried (or changed to)
synthetic and my engine suddenly failed, therefore it had to be the
oil." I've seen the same stories about brands of oil whether mineral
or synthetic, oil filters, gasoline, air filters, coils, spark plugs
and even batteries. You can find them all over the internet. Usually
the stories are about products that thousands if not millions of
people have used for years. While I'm not willing to say that the
stories aren't true, I do believe that these stories are not true for
the vast majority of the individuals using the particular products.

There are some distinct advantages to synthetics. The film formed is
much tougher than with mineral oils. This allows the oil to protect
engine parts better when oil pressure drops. Synthetics typically are
slicker than mineral oils this can significantly lower the temperature
of an engine and increase efficiency.

The disadvantages is that the lighter grades of oil and the better
detergent properties can cause some problems in older engines. In
older engines sludge from mineral oil will help seal shrinking gaskets
and seals. The better detergents in synthetics dissolve this junk and
the engine starts to leak. Early versions of Mobil 1 was especially
bad this way but Mobil changed the formulation prety quickly. This was
over 20 years ago but the stories are still told like it happened last
week.

It all boils down to what you want to believe. My view is that Mini
drivetrains are a lot like a motorcycle's. The engine and the gearbox
share the same oil. Otherwise there isn't much difference technically
in the design. Motorcycles don't show any systemic problems using
synthetic oils.

Cheers,

Kelley

NO NO NO  don't use synthetic

I can testify that using synthetic engine oil in my cooper blew the gear
box and the same thing happened in my brother in laws mini. ( I doubt it was
a coincidence )
I have owned minis for around 20 years and never had a box blow on me until
I used synthetic. You can read all the paperwork you like saying that there
is no difference between synthetic and mineral oil but I can assure you from
experience there is.
The scientists also said that eating beef was safe but time proves again
and again  that scientists are full of sh+t.......

If you value your mini use only quality mineral based oils

fragged

it may have been castrol but i cant remember exactly and i couldnt tell you
what my bro in law used but I find it more than bad luck for 2 minis to
suffer the same fate after using the same type of oil considering one was a
72 van with an uprated gearbox and the other was a 92 cooper with a standard
box makes the oil even more suspect

fragged