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.

 

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?

 

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.

 

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')

 

Hi,

Coolant level is not dropping
Have not been able to smell the steam yet
No visible coolant leaks
No oil leaks

Thanks.

 

Yup, that's it.

Thanks Bill.

 

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..

 

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.

 

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.

 

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.

 

I believe that I forgot this link.

http://www.repairfaq.org/filipg/AUTO/F_Slick_501.html

 

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