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Help! During radiator filling the level won't decrease

S

speedbird1229

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I'm kinda with the rest of the group on this one. If you've secured the hose so that it doesn't blow off now, then it doesn't really sound like much of a problem.
You sound like you've double-checked everything and replaced most of the usual stuff and then some.
Checking for line pressure by squeezing the radiator hose when hot isn't exactly a great measurement tool. I know on my car that the radiator hose is naturally quite a bit sturdier than the radiator hose use on a 4-banger daily driver. Even when hot, my radiator hose doesn't have much give.

If the car ain't overheating and you aren't losing any more coolant, then be satisfied that you have a properly working vehicle.

As for the reservoir not having much coolant in it when the car is up to temps, same here. Mine almost never has coolant in it, even on the hottest days of 100°+ outside temps. But I know my system is 100% good.
If you are concerned about adding coolant to the system without popping the radiator cap, just put coolant in the overflow tank and let the system suck up the extra juice on it's own. Whatever it doesn't need will remain in the overflow.

Sounds like you're good to go, guy! :thumb
Thanks for this. I was looking for exactly the same kind of information you gave - how's someone else's system performing. Everyone has been telling about different problems I might be having with the engine and I don't blame anyone because it's just very hard to investigate those things via a forum. Perhaps it's normal then how it performs, if you're sure 100% that yours is ok.

Jack - thanks for the extra clarifications :) I think I was a bit confusing with the "coolant dripping from radiator" part. I meant that if I run the engine with radiator cap off, is it then supposed to be dripping out from the cap hole? Still no? The level should stay even with the radiator neck when engine is running?
 

entropy454

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Im not an expert but I think your saying this...

If I leave the cap off, once the car starts warming up, should the coolant level be rising up and start to run out of the radiator cap hole.

I am pretty sure that is common because your coolant system , once warmed up, is a pressurized system. Its not suppose to pour or shoot out, but in the past I know my cars sometimes would slowly raise there level and come out where the cap is supposed to be.

In the past, I always figured that was due to being overfilled and the excess should have done in the overflow. My car didnt have an overflow at the time.
 

Evolution1980

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I meant that if I run the engine with radiator cap off, is it then supposed to be dripping out from the cap hole?
I am pretty sure that is common because your coolant system , once warmed up, is a pressurized system. Its not suppose to pour or shoot out, but in the past I know my cars sometimes would slowly raise there level and come out where the cap is supposed to be.
Yes, as stated because pressure builds as the system heats up. Fluid will seep out via the fill spout (sans cap) because it's taking the path of least resistance. Put the cap back on and when the system's warm, if it needs the additional space to 'expand', it will go into the overflow tank. As it cools ('contracts') it will pull the fluid back from the overflow. Having a little in there when the system is cold is OK. Having some in there when the system is hot is also OK, but not a requirement to be considered working "correctly".
 
S

speedbird1229

Guest
Yes, as stated because pressure builds as the system heats up. Fluid will seep out via the fill spout (sans cap) because it's taking the path of least resistance. Put the cap back on and when the system's warm, if it needs the additional space to 'expand', it will go into the overflow tank. As it cools ('contracts') it will pull the fluid back from the overflow. Having a little in there when the system is cold is OK. Having some in there when the system is hot is also OK, but not a requirement to be considered working "correctly".
Thank you. It does make sense for sure. So, as I understand it is not an absolute requirement for the fluid to flow into the reservoir once the engine is warming up or is warm? I assume that keeping as much fluid as possible and at higher pressure is needed to raise the boiling temperature?
 

Evolution1980

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Thank you. It does make sense for sure. So, as I understand it is not an absolute requirement for the fluid to flow into the reservoir once the engine is warming up or is warm?
Correct. It is not a requirement.

I assume that keeping as much fluid as possible and at higher pressure is needed to raise the boiling temperature?
Technically/Scientifically speaking, "No". The boiling point will not change regardless of the quantity of fluid. Just like water that boils at 212°F, it doesn't matter how much there is, it's still gonna boil at the same temp, it's just gonna take longer for the entire quantity to reach that state/temperature.

In the case of your car's cooling system, quantity serves two purposes (but the two are so closely related, it could be one in the same).
Purpose 1: Greater quantity of coolant can move/hold/carry (pick your word) more heat energy. More heat can be absorbed with more fluid where it is then dissipated as it passes through the radiator.
Purpose 2: The quantity required by the system is set so that it can constantly be in contact with the areas that require heat to be dissipated.

As stated above, air in any fixed-quantity fluid system is a generally bad thing- cooling system, brake system, auto transmissions, etc. The liquid won't compress or expand but air does. Too much air in the system upsets the fluid flow and thus the purpose, or effectiveness, of the fluid (cooling or lubrication) is lessened.

...as I understand it. I'm no mechanic nor engineer. :)

-------
POST TECHNICAL EDIT: inducing pressure into a closed system will raise the boiling point of the enclosed fluid. (That's how water cooling works in reactors.)
 

entropy454

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My 71 nova never had an overflow container. It just had a hose that let overflow pour right onto the ground. So an overflow container is not neccesary, at least it wasnt for the nova.
 

entropy454

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Pressure(air pressure or pressure in your closed coolant system) and water/anti-freeze mix raises the boiling point of your cooling system.

For example, straight water in your radiator would not boil over at 212.
I belive the water heating up causes pressure in your cooling system. This pressure raises the boiling temp of water. Your antifreeze (has a larger effect on the boiling point I belive) making cars normally boil over at 240+?

Does that all sound right to everyone? :) This is my understanding of the functioning of a closed cooling system for a car.
 
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Having a little in there when the system is cold is OK. Having some in there when the system is hot is also OK, but not a requirement to be considered working "correctly".

Most tanks have Hot and Cold lines and the coolant should generally be between those two lines.

The cap certainly works backwards because I've seen the coolant level decrease from the reservoir after the engine has cooled down from warm.

Coolant level in radiator has always been to the neck. I've also done the re-filling procedure to run it without the cap and then re-fill once the engine draws it from the radiator.

In order for the cap to allow coolant out of the radiator you have to exceed the pressure release setting of the cap. I used to know how much one pound of pressure increased the boiling point of water but that's a long time ago and I'm old. Suffice it to say that the cap will likely increase the boiling point to 250 - 260 psi. Until you get to those temeratures, the cap won't release because there is not enough pressure.

You say your car is running at 200 - 210. I would be surprised if you saw any release when the car is running and may only get a minimal release when the car is turned off and the coolant heats up due to no cooling air.

In my closed systems I never open the cap. I monitor the overflow tank and add coolant to a cold car if it ever goes below the cold line on the tank.
 

Evolution1980

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Pressure(air pressure or pressure in your closed coolant system) and water/anti-freeze mix raises the boiling point of your cooling system.

For example, straight water in your radiator would not boil over at 212.
I belive the water heating up causes pressure in your cooling system. This pressure raises the boiling temp of water. Your antifreeze (has a larger effect on the boiling point I belive) making cars normally boil over at 240+?

Does that all sound right to everyone? :) This is my understanding of the functioning of a closed cooling system for a car.
Antifreeze, or ethylene glycol, both raises the boiling point of water and lowers it's freezing point.

Continuing my "if I understand correctly but certainly may not" commentary...:L...if you were running pure water in your cooling system, higher pressure may raise the boiling point a bit, but the steam generated has TONS more energy than the water itself. Your hoses or other parts of the system would fail under the intense heat/energy created by the steam. And that's exactly why parts of the system (radiator cap, overflow tank) were engineered the they way they were.

Side note: Ethylene glycol is also very toxic and tasty (YUM!) to animals, humans included. That's one of the reasons 'we' shouldn't let it drain on to the ground.
 
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speedbird1229

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This is a cool discussion going on, I'm getting some very useful information from this! It's all kind of beginning to make more sense to me. If the cap should really begin releasing remarkable amount of fluid to the reservoir when the water temperature reaches around 250 F, then everything seems to be working properly.

There are those COLD and HOT marks on the reservoir. I assume those are simply the lower and upper limits for the level, not marking where the level should be with cold engine and where it should raise when the engine is warm? This would mean releasing a lot of coolant to the overflow tank and wouldn't really match with the theory anyway, I guess :)

By the way, here's the upper rad. hose where I have the clamp in the new (hopefully correct) location and you can see the location where it used to be at the very end of the hose. I guess it was installed wrong.

upperradiatorhose_newclamp.jpg
 

Evolution1980

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By the way, here's the upper rad. hose where I have the clamp in the new (hopefully correct) location and you can see the location where it used to be at the very end of the hose. I guess it was installed wrong.
Ummm...the clamp looks a bit far down to me. The original location is more correct. I think there is a nib about 1-1.5" down on the neck of the radiator outlet. The clamp should be behind that nib (towards the front of the car). That nib is more or less what keeps the clamp from sliding down the hose and also puts a small impression into the hose to help keep it in place as well. Maybe your aftermarket(?) radiator doesn't have that ;shrug
None of us here could tell you what your radiator has. Only you can tell us that.
 

Phill

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Id have to agree about the clamp looking like its to far down the hose. maybe you can put two clamps on it, better safe then sorry.
check out post #9. Wayne mentions something about the heater core and proper procedure in filling the system with coolant. if the heater wasnt turned on when filling the system you could have air in the system.
by the way nice looking vette.

:w
 
S

speedbird1229

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Thanks for the tips. It does look like too far back but on this radiator I have the "end stop" right after the clamp's current position. In the old location there's just about half an inch of slippery surface, then the pipe goes thinner.

Adding two clamps is a good idea, I think I'll do it.

The radiator is not original, it was installed last summer by the previous owner and I can find out what brand it is because I talked to the mechanic who did this job - he even has the box still sitting in his garage somewhere :)
 
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There are those COLD and HOT marks on the reservoir. I assume those are simply the lower and upper limits for the level, not marking where the level should be with cold engine and where it should raise when the engine is warm?

The coolant should actually be between those marks.

Is that the preformed hose or one of the generic aftermarkets?
 
S

speedbird1229

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The coolant should actually be between those marks.

Is that the preformed hose or one of the generic aftermarkets?
I see. This question I cannot really answer because it was replaced by the previous owner. I can ask if his mechanic knows, he probably doesn't.
 
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Disconnect it. If it goes straight and has to be be forced into position it is not the pre-formed hose.

This is from Zip's web site.

M-2436.JPG


Eckler's has two hoses. The late 79 hose is the same as this. The early hose is different.
39245.jpg


It's hard to tell but your hose doesn't look like either of these. The hose coming off may have been as simple as pressure where the hose connects to the radiator caused by forcing what appears to be the wrong hose compounded by poor clamp placement.
 

Evolution1980

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Disconnect it. If it goes straight and has to be be forced into position it is not the pre-formed hose.
For as much as he's questioned his setup, if it's working now, I wouldn't recommend he take anything apart and possibly induce (more?) air into the system. Put both clamps on and leave it be. :L :beer
 

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