Radiator steam question

Hi all.
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?
Thanks.
Colin.
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It indicates that you are not doing a good job of troubleshooting. Since this happens frequently, one day you have to take the time too let the car warm up just enough that is not steaming yet, then pop the hood and let it warm up until it does.
Are there visible signs before you start the car? Does it happen every time, most times, or just once in a while?
It can be a slight leak at a thermostat gasket, a radiator hose clamp, heater hose, etc. I can't see it so it is up to you to take the time to find it.
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Thanks Ed.
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Might want to check the radiator cap - that's what it was on my '95 Olds 88 with identical symptoms. Engine would be heating up and about the time the thermostat would open (slightly high reading on the temp gauge, then a dip in the reading) there would be a wisp of steam from under the hood only when I was at a stop light.
Just a thought.
Bob
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