Coolant leak when it's cold

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Patman

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I've noticed when I pop the hood on my LT1 Firebird that when it's very cold out (around 0F or less) that I see a few drops of coolant on the elbow going into my throttle body (I have no idea how it gets up there!) but I also see no evidence of leaking from anywhere.

The water pump is pretty high up on this engine (right under the throttle body actually) so is it possible that in extreme cold only I might get a slight leakage but it'll be fine once the weather warms up?

Has anyone else experienced minor coolant leaks when it's extremely cold? I saw no coolant leakage at all yesterday morning when it was closer to 20F outside.
 
My '95 5.0 'stang leaks from the overflow bottle / radiator area when the temps are real cold. Every 4-5 months, it gets low enough to trigger the "low coolant" light, at which point adding 1 pint to 1 Quart brings things back to normal.

It's been doing this for 2 years, and hasn't gotten any worse.

I'd be fearing for the life of your optispark if you have a leaking water pump.
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Patman, I know how it gets there
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On our engines, coolant flows thru the throttle body. Perhaps the hose connected to the throttle body has slid back a bit or is becoming worn and cracked slightly.


Jason
 
Yes! the other morning it was -5F and I had a small puddle under my car. 250mL maybe at most. Didn't have time to check it out but I haven't noticed it again and my level is lower but still ok. Beats me.
 
I have had similar problems with my Camry when temps get down into teens. Almost swear that the head gasket has minute cracks that enlarge when very cold (gasket shrinks) to permit coolant to leak into cylinders. This has been common for past two years in cold weather. Nothing in oil per oil analysis and this year I have seen some drops underneath engine as well. Cannot figure out what is going on. Level has dropped some also.

Sure would love some experts to chirp in with opinions for all of us affected by cold weather coolant leaks
 
My experience is that the Havoline Dexacool easily seeps past any hose connection that is not near perfect. I have the same problem on cold nights with a van that I've converted to Dexacool. The green stuff will not do this..

You have to have a smooth clean fitting and a relatively smooth clean hose and then you generally can get a leak free seal. But I've given up on my lower radiator hose until Spring when I intend to just buy a new hose and replace it after I polish the radiator outlet where the leak occurs.
 
It's not from the hose to the throttle body, as I see absolutely no evidence of leakage there, the hoses look in great shape and there is no residue. I can't see any residue of coolant anywhere, except for on that rubber intake elbow going into the TB.

And I'm definitely worried about my optispark, however I see no coolant dripping downwards at all, not a single drop is ever found on the ground. Weird for sure.
 
My 95 Firebird does not use Dexcool though, it was one of the last years to use conventional green stuff in these cars.
 
quote:

Originally posted by Patman:
It's not from the hose to the throttle body, as I see absolutely no evidence of leakage there, the hoses look in great shape and there is no residue. I can't see any residue of coolant anywhere, except for on that rubber intake elbow going into the TB.

And I'm definitely worried about my optispark, however I see no coolant dripping downwards at all, not a single drop is ever found on the ground. Weird for sure.


On the intake plenum:eek:

Is this after it has set overnight, or after driving around when it is cold? The only thing I can think of is when cold, coolant is leaking, then when it is driven, coolant is blowing up there(weep hole maybe?). Would be very mysterious for coolant to appear there without driving the car.

Jason
 
I notice it when I arrive at work after having driven 25 miles. It's not on the intake plenum, but on the rubber elbow leading to the throttle body. This morning it was 10F out and I didn't get any additional leakage.
 
quote:

Originally posted by Patman:
I notice it when I arrive at work after having driven 25 miles. It's not on the intake plenum, but on the rubber elbow leading to the throttle body. This morning it was 10F out and I didn't get any additional leakage.

I thought that the entire intake tract from the filter to the throttle body was considered the "intake plenum". Perhaps I'm incorrect. Either way, I know what you are talking about now.

I would check around for a coolant leak at all hose connections in the morning before you run the car to see if anything has seeped out. My best guess
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The intake plenum is simply another word for intake manifold.

From what my f-body friends are telling me, it looks like I'm simply seeing the beginning signs of a failing water pump. It starts out leaking a tiny bit out the weep hole in cold weather, and that leak drips on the belt which then flings it upwards.

So sooner or later I'm in for a big repair bill, unless the problem can hold out a few weeks till warm weather arrives, then a friend of mine can do it (it's a 3 hour job to change it so it's not something you want to do in cold weather)
 
quote:

Originally posted by Patman:
The intake plenum is simply another word for intake manifold.

From what my f-body friends are telling me, it looks like I'm simply seeing the beginning signs of a failing water pump. It starts out leaking a tiny bit out the weep hole in cold weather, and that leak drips on the belt which then flings it upwards.

So sooner or later I'm in for a big repair bill, unless the problem can hold out a few weeks till warm weather arrives, then a friend of mine can do it (it's a 3 hour job to change it so it's not something you want to do in cold weather)


That was my first guess after you said it was on the elbow. I helped one of my buddies this past summer do his water pump. Keep an eye on it. It might make it for a few weeks, but at what cost on the opti?
 
my friends family has been through like 5 pontiac bonnevilles, 4 out of the 5 had a leaky intake plenum, guess its a big problem with some 3.8's
 
Just an update here. It was very nice here this weekend, 40F both days! I drove my car at least 70 miles this weekend and not a single drop of coolant appeared, even after pushing the car hard.

So it's definitely cold weather related. Too bad it's getting extremely cold again later this week.
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As much as I hate additives of any kind I bit the bullet and placed a coolant system conditioner in two engines that have experienced consistent coolant loss over the past few months. (head gasket I think in both but nothing on oil analysis) One received a Prestone Super Sealer the other a Bahrs. Both systems have now apparently stop losing coolant and the level has been normal for a week now. I hate putting that crap in, reminds me of shredded wheat cereal with all the particles floating around. But, so far it seems fine. Probably blow next week though.
 
Sometimes when the engine cools down, the coolant will leak from the hose connection. I have had that happen before. Or one of the bolt that enter into a coolant passage is allowing the coolant to leak a minute amount.

But the bad hose clamp is my guess. It took me a while to discover it was a loose hose clamp because the coolant was alwsy some distance from the source of the leak. You might need to replace the hose if these are the originals. 8 yrs is a long time.
 
My normal procedure for this problem is to first tighten any clamps with adjustment on them after the engine is all warmed up. Then add another airplane clamp to all the fittings and tighten the crap out of them. Check it again in a couple of weeks and it should be good to go.
 
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