I have a 1994 Chev with 125k miles and the original radiator. It
has been flushed and filled every 2 years.
Recently, I have noticed that just after the car warms up and I am sitting
at a traffic light, I can see wisps of steam/smoke that seem to be coming
from the radiator. I have pulled over to check under the hood, but by
that time, the steam has stopped. It usually lasts only for a couple of
minutes and then stops and does not happen again until after the engine
is stopped, cools off and is restarted. There are no coolant leaks and
the water pump was replaced about 10 months ago.
It is most noticeable when it is raining or on a cool morning. I am
wondering if some moisture may be accumulating somewhere on the radiator
and then condensing once the radiator heats up.
Like I said, the steam is only visible shortly after startup. Things
are fine for the rest of the drive.
Does this indicate a problem with the radiator or possibly the thermostat?