On Sun, 21 Jan 2007 07:28:50 -0700, "Michael Pardee" wrote:

>The Honda coolant is not as critical as the power steering fluid or the ATF,
>but it's pretty cheap insurance against water pump seal trouble. Being
>premixed, there is also no concern about it being diluted with tap water,
>which is a very bad idea. Aftermarket thermostats, on the other hand, have
>earned a reputation for flaky operation. I gave up on them about a decade
>ago.

Well, I'm afraid I did not have a choice at the time when I found my
radiator almost empty and use tap water to mix with the Prestone
antifreeze as premixed one was not available. I'm taking the car in to
my mechanic for 240 K scheduled maintenance (same as 60 K) and tell
him to drain the cooling system and refill it with premixed coolant.
As he deals with all kinds of Japanese cars, not just Honda, I am
making sure he is going to use Honda brand ATF which I bought
yesterday at a nearby Honda dealer's part store. I also bought new
spark plugs there and oil filter. As before I'll have him use the
Castrol 5-30 oil that I provide as he normally uses Chevron brand.

From the answers so far I have not seen many that addressed the
possible source of coolant vapor getting into the passenger
compartment and condensating on the cold windows. My first thought was
a heater core leak but that does not explain how the vapor gets in
with the heat turned off. I figure it must be a very small leak if it
does not create noticeable drop in coolant level or drips under the
engine. I'll see what the mechanic might find tomorrow but if he
suggest replacing the heater core I would hesitate to take that route
due to the big labor involved with it. In that case I might try first
to put that "Liquid Aluminum" radiator silant powder into the coolant
and see if that helps. On the other hand some of you would probably
say that it could hurt more than help. Any thoughts about it?

JP