You've got a leak almost for sure. If all your hoses are tight, check for a
pin hole leak somewhere.
They are common at the top of the engine. There's a metal pipe that runs to
the heater hose on top of the engine that can get a pin hole in it too.
You will very slowly lose fluid, so keep an eye on it.
You can get it pressure tested, but that's costly, so use your noise and
eyes.

--
Bob Noble
http://www.sonic.net/bnoble
<youngrobbm@gmail.com> wrote in message
news:1194413074.379963.94550@v23g2000prn.googlegro ups.com...
>I recently bought a 1991 Subaru legacy turbo with 156,000 miles on it.
> A little less than a month ago, I was driving and one of the main
> radiator hoses popped off, spilling all of my coolant. I put the hose
> back on, refilled the coolant, and everything seemed to be fine. Just
> the other day I started noticing small amounts of steam (may be smoke,
> is a white vapor but does not smell like smoke) coming from under my
> hood when I am at a stop light after driving for a while. The temp
> guage reads normal, and the engine runs fine. Any suggestions? It may
> be a coolant leak, because the steam smells somewhat like vaporized
> coolant.
>

Bob Noble wrote:
> You've got a leak almost for sure. If all your hoses are tight, check
> for a pin hole leak somewhere.
> They are common at the top of the engine. There's a metal pipe that runs
> to the heater hose on top of the engine that can get a pin hole in it too.
> You will very slowly lose fluid, so keep an eye on it.
> You can get it pressure tested, but that's costly, so use your noise and
> eyes.
>
That model had a radiator, a separate header tank which had the
pressure cap, and then the overflow bottle. On mine that separate
*plastic* header tank developed a split. *Plastic welding* was not
successful and it took visits to several wreckers to find a replacement.

I think on later models which had the separate tank the tank was made of
metal.

Careful taking off the pressure cap (don't ask me how I know)