I wouldn't flush anything. I think a drain and fill at recommended
intervals is just fine unless you have neglected the vehicle and deposits
are forming.

Be sure to use distilled water upon refilling 50/50 with your coolant.



"Elle" <elle_navorski@nospam.earthlink.net> wrote in message
news:seX6e.5012$yq6.374@newsread3.news.pas.earthli nk.net...
>I am draining, refilling and possibly flushing my 164k miles, 1991 Civic
> LX's cooling system tomorrow. I've done it myself at least three times
> over
> the years, but not quite the same way each time. A few questions:
>
> 1.
> My Chilton's manual says I can "back flush" the system by removing the
> thermostat and sticking a "high pressure" hose in the housing, until clear
> water runs out the radiator hose (presumably the one disconnected at the
> housing). Is this really a "backflush," or is it more correctly a forward
> flush but with higher pressure than the engine normally sees? If it's a
> forward flush, I'm inclined to skip this, unless someone says they feel
> it's
> worthwhile for a car this age.
>
> 2.
> If I don't do 1. above, then I'm going to do my best to remove the engine
> drain plug. I had it off once before, but as many here know, it's badly
> located and tough to remove.
>
> 3.
> If I do neither of the above, I'm going to fill and drain until the water
> is
> clear. I have the capacity specs. on the engine coolant passages, etc. and
> am confident about the dilution I will achieve. I've done this in the
> past.
>
> No need to caution me about the coolant to use. I know people swear by
> Honda
> coolant, but I've been using the orange Havoline Dex cool and am quite
> satisfied (knock on wood).
>
>