1994 Caravan - radiator steam question

Hi all.
I have a 1994 Caravan with 125k miles and the original radiator. It has been flushed and filled every 2 years.
Recently, I have noticed that just after the van warms up and I am sitting
at a traffic light, I can 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.
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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BlueBuyYoo wrote:

Not enough info. Is the coolant level dropping? Does the steam smell sweet like antifreeze? Could it actually be smoke from a leaky valve cover gasket dribbling oil on an exhaust manifold rather than steam?
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Hi,
Coolant level is not dropping Have not been able to smell the steam yet No visible coolant leaks No oil leaks
Thanks.
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BlueBuyYoo wrote:

Then if it IS a leak, its a really, really small one.

That would actually be very helpful to do. Follow other advice to let the vehicle warm up in the driveway with the hood up and see what you can see/smell. If it smells sweet, it is likely coolant. if it smells awful, its likely oil burning on a hot surface.

Well, if the oil drips on a manifold and then burns, it won't leave much visible residue..
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If the problem is as you state it... That is, it happens ONCE per warm-up cycle and only as the engine does it's initial warm-up...
At this time of year, it's more than likely condensation from the air on the OUTSIDE of the radiator. In the old days with mechanical fans you'd never see it as there was always a 'draw' of air into the engine compartment. But with electric fans on cars now, if the fan hasn't started the steam from the condensation coming off now can come up in front of the hood and you see it. In fact, it's very likely to come up, as there might be a convection from the engine warming making the air come OUT of the engine compartment through the radiator when the car is still.
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Mike Y wrote:

That could be. Or it could be a small leak (hose joint, hose pin hole, water pump, radiator leak, radiator drain leak, freeze plug, intake/head gasket, yadda yadda yadda...) acting like that (pooling, then boiling off, and not being enough vapor to be visible after initial warm up and boil-off). Also check radiator cap (or pressure bottle cap - I don't know which it has) - they can play these kinds of invisible leaks games on you (in fact if you can't identify the source, replace that - it's probably due whether it's actually leaking or not.
If I was the OP, I'd wait until I could take 15 minutes on a Saturday and, if I could not find a small pool of coolant (or condensation that Mike mentions), I would start it up with the hood up and watch for the puff of vapor as it warmed up to see if I could localize its source.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
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Yup, that's it.

Thanks Bill.
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sitting
thermostat?
warm-up
the
from
I had this issue with my GLH Turbo. I put Slick-50 in the thing, and it would take FOREVER to warm up. I moved from Texas to New England and I started seeing the steam about a mile or so from the house on cool fall mornings where the hood was wet from condensation when I started out and then stopped at a light about 2 miles from the house. First time it happened I almost went into a panic, pulled over and popped the hood. Finally figured out what it was.
That was the first car I had owned that didn't have a mechanical fan and I was in an environment that could cause this. I had a Pontiac Phoenix before the Dodge, but I liven in Texas the whole time I owned that vehicle.
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On Thu, 18 Oct 2007 13:41:07 -0400, Mike Y wrote:

Personally, I would stay away from Slick 50, and all other additives containing PTFE. If the world's largest producer of Teflon (DuPont) states that it is not suitable for automotive engine internal application, then I would listen. I can't remember how many frying pans, coated in Teflon, that I have thrown out over the years because the coating flaked off of them, and they got nowhere near as hot as some of your internal engine components!
Speaking of your GLH Turbo, I used to own an '86 GLHS.
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I have to disagree with that. Typical frying pan temps when frying eggs are between 250-350 F. When the frying pan is just sitting there on the burner without anything cooking on it to wick away the heat, it gets a lot hotter.
Teflon cookware is for the birds anyway. Either cast iron with a porcelain coating (if you got the time) or stainless steel is the way to go.
Ted
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On Thu, 18 Oct 2007 13:41:07 -0400, Mike Y wrote:

I believe that I forgot this link.
http://www.repairfaq.org/filipg/AUTO/F_Slick_501.html
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On Wed, 17 Oct 2007 14:05:01 +0000, BlueBuyYoo wrote:

I used to own a '94 Caravan (3.0 V6, 3spd) as well, and I noticed the same thing. What I found was that outside moisture was being sucked onto the hot radiator surface when the cooling fan turned on. When the moisture would hit the hot surface, it would be turned into steam.
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