"Harry K" > wrote in message
oups.com...
>
> wrote:
>> "No Spam" > wrote in message
>> . com>
>>
>> > My girlfriend has a 1995 Mercury Sable GS with Overdrive
>> Transmission.
>> >
>> > We don't use overdrive around town because we have both heard
> people
>> > say using it for town (stop and go) driving stresses it and to only
>> use
>> > it on the freeway and on long trips.
>> >
>> > I have also heard it is ok to use Overdrive around town.
>>
>> It's perfectly fine to use Overdrive all the time, except sometimes
>> when going down long hills, and the people who advised against it
> have
>> obsolete information or owned one of the first Ford 4-speed automatic
>> overdrive transmissions, which would sometimes make the engine stall
> in
>> panic stops if in overdrive. If you don't use overdrive in highway
>> traffic, not only will your fuel economy be noticeably worse, but
> your
>> transmission torque converter may run hotter since its lock up clutch
>> remains disengaged (but some cars lock up this clutch even in lower
>> gears)
>>
>> Avoid additives except possibly an occasional bottle of Dry Gas (to
>> remove water from the gas tank) or Techron (removes carbon from fuel
>> injectors, pistons, heads, and intake valves). Don't overdo them.
>
> Same opinion as all others and as layed out in your manual. One
> exception. HEAT is not snake oil. It is one of many brands of 'dry
> gas' to remove water from the gas tank. You should use one
> occasionally, especially in winter. I usually throw one in at the
> beginning of winter and another in spring.

But does it improve fuel economy?