Many of the older, better-known = oil treatments on the market do
not make claims nearly so lavish as the = new upstarts. Old standbys
like Bardahl, Rislone and Marvel Mystery Oil, = instead offer things
like "quieter lifters," "reduced oil burning" and a "cleaner
engine."

Most of these products are made up of = solvents and detergents
designed to dissolve sludge and carbon deposits inside = your engine
so they can be flushed or burned out. Wynn's Friction = Proofing
Oil, for example, is 83 percent kerosene. Other brands use
naphthalene, = xylene, acetone and isopropanol. Usually, these
ingredients will be found in = a base of standard mineral oil.

In general, these products are designed = to do just the opposite of
what the PTFE and zinc phosphate additives claim = to do. Instead of
leaving behind a "coating" or a "plating" on your engine surfaces,
they are designed to strip away such things.

All of = these products will strip sludge and deposits out and clean
up your engine, = particularly if it is an older, abused one. The
problem is, unless = you have some way of determining just how much
is needed to remove your = deposits without going any further, such
solvents also can strip away the = boundary lubrication layer
provided by your oil. Overuse of solvents is an = easy trap to fall
into, and one which can promote harmful metal-to-metal contact
within your engine.

As a general rule of thumb these = products had their place and were
at least moderately useful on older = automobile and motorcycle
engines of the Fifties and Sixties, but are basically = unneeded on
the more efficient engine designs of the past two decades.