Re: Coolant Vanishing: '95 Civic EX 1.6 - Attn Tegger and Techs
 

On Feb 21, 8:36 pm, Tegger <teg...@tegger.c0m> wrote:
> motsco_ <mots...@interbaun.com> wrote innews:13rpah1bmfjdo50@corp.supernews.com:
>
>
>
> > Volvos and Dodge products that I owned had pressurized reservoirs. The
> > coolant level in them went up and down with temperature, but the HONDA
> > isn't supposed to, since it's reservoir isn't under pressure at all.
> > Boiling hot coolant isn't supposed to take up much more room than cold
> > coolant, [...]
>
> But it does. ALL materials expand with heat.
>
> The reservoir level naturally rises and falls as the coolant heats and
> cools. This is the purpose of the various seals in the rad cap, and for the
> very presence of the (unpressurized) reservoir in the first place.
>
> You don't have to take my word for it. Check your own reservoir's level at
> dead-cold. Drive the car to full-hot, then have another look at the level.
> It will be at least a half-inch higher.
>
> Coolant is constantly traveling in and out of the reservoir with every
> heat-cool cycle. It's a normal and necessary feature of a modern sealed
> cooling system's operation.
>
> --
> Tegger
>
> The Unofficial Honda/Acura FAQwww.tegger.com/hondafaq/

my idle question is, how much negative pressure is required to suck
the coolant in. obviously, the spring keeps the in valve shut at zero
pressure, but when the coolant cools off, there's negative pressure in
the block which sucks the coolant from the reservoir. we assume the
pressure of the spring on the valve leading from the block to the
reservoir is what it's labeled as, but i just wonder how much residual
vacuum remains in the block when the spring shuts the input valve. for
no reason other than idle curiosity.

Re: Coolant Vanishing: different direction Coefficient_of_thermal_expansion
 

z wrote:
> On Feb 21, 7:44 pm, Grumpy AuContraire <Gru...@ExtraGrumpyville.com>
> wrote:
>> Um, I said "boiling point" as a yardstick that is subject to change
>> depending on how much pressure the liquid is subject to at the time.
>
> of course, the coolant at operating temp is quite a bit above the
> "boiling point" of 212 degrees, that's why it's pressurized.

Actually, the thermostat on most cars is below 212 F. And the boiling
point is above 212 with the antifreeze.

> in other words, you've gone from about 500 fahrenheit degrees above
> absolute zero, to about 700 degrees. as a first approximation, that's
> gonna see a 40% expansion. i hope your hoses don't expand that much.

It's actually going to be about 4% from O to 80 c (about 180 F).

http://www.simetric.co.uk/si_water.htm

Coolant will expand by a different amount, because it has antifreeze and
other additives in it.

Solids don't increase by 40% in volume from -40 F to 212 F. Why would
you think water would?

Jeff

Re: Coolant Vanishing: different direction Coefficient_of_thermal_expansion
 

z wrote:
> On Feb 21, 11:49 am, motsco_ <mots...@interbaun.com> wrote:
>> The Honda coolant expands a bit and builds pressure, but it's the hoses
>> that probably absorb most of the expansion, not the reservoir. If you
>> were talking about gasoline expanding, that's very different. Water
>> doesn't compress, and until it boils it doesn't expand much at all.
>
> ?? the average honda owner, meaning me, can see a rise of maybe an
> inch or so in the reservoir after the engine is hot.

=======================

Yep. That's exactly what I said in the first place:

> I've owned six Hondas and the level in the reservoir never changes more than about 1", hot or cold, summer or winter.

'Curly'

Re: Coolant Vanishing: different direction Coefficient_of_thermal_expansion
 

z wrote:
> On Feb 21, 11:49�am, motsco_ <mots...@interbaun.com> wrote:
>> The Honda coolant expands a bit and builds pressure, but it's the hoses
>> that probably absorb most of the expansion, not the reservoir. If you
>> were talking about gasoline expanding, that's very different. Water
>> doesn't compress, and until it boils it doesn't expand much at all.
>
> ?? the average honda owner, meaning me, can see a rise of maybe an
> inch or so in the reservoir after the engine is hot.

try driving up grapevine [california i5], in summer, at 95. i guarantee
you'll see more than that. unless there's something wrong, it won't
overheat, but fluid level will be right at the top of the bottle.

Re: Coolant Vanishing: '95 Civic EX 1.6 - Attn Tegger and Techs
 

z wrote:
> On Feb 21, 8:36�pm, Tegger <teg...@tegger.c0m> wrote:
>> motsco_ <mots...@interbaun.com> wrote innews:13rpah1bmfjdo50@corp.supernews.com:
>>
>>
>>
>>> Volvos and Dodge products that I owned had pressurized reservoirs. The
>>> coolant level in them went up and down with temperature, but the HONDA
>>> isn't supposed to, since it's reservoir isn't under pressure at all.
>>> Boiling hot coolant isn't supposed to take up much more room than cold
>>> coolant, [...]
>> But it does. ALL materials expand with heat.
>>
>> The reservoir level naturally rises and falls as the coolant heats and
>> cools. This is the purpose of the various seals in the rad cap, and for the
>> very presence of the (unpressurized) reservoir in the first place.
>>
>> You don't have to take my word for it. Check your own reservoir's level at
>> dead-cold. Drive the car to full-hot, then have another look at the level.
>> It will be at least a half-inch higher.
>>
>> Coolant is constantly traveling in and out of the reservoir with every
>> heat-cool cycle. It's a normal and necessary feature of a modern sealed
>> cooling system's operation.
>>
>> --
>> Tegger
>>
>> The Unofficial Honda/Acura FAQwww.tegger.com/hondafaq/
>
> my idle question is, how much negative pressure is required to suck
> the coolant in. obviously, the spring keeps the in valve shut at zero
> pressure, but when the coolant cools off, there's negative pressure in
> the block which sucks the coolant from the reservoir. we assume the
> pressure of the spring on the valve leading from the block to the
> reservoir is what it's labeled as, but i just wonder how much residual
> vacuum remains in the block when the spring shuts the input valve. for
> no reason other than idle curiosity.

almost zero. there are two springs - one for high pressure exit, the
other is practically zero return. unscrew the radiator cap when cold
and see how much vacuum there is when you release.

Re: Coolant Vanishing: '95 Civic EX 1.6 - Attn Tegger and Techs
 

z <gzuckier@snail-mail.net> wrote in
news:eb120ecd-16d6-44df-9bf3-3c7fc9243265@41g2000hsc.googlegroups.com:


>>
>>
>
> my idle question is, how much negative pressure is required to suck
> the coolant in. obviously, the spring keeps the in valve shut at zero
> pressure, but when the coolant cools off, there's negative pressure in
> the block which sucks the coolant from the reservoir. we assume the
> pressure of the spring on the valve leading from the block to the
> reservoir is what it's labeled as, but i just wonder how much residual
> vacuum remains in the block when the spring shuts the input valve. for
> no reason other than idle curiosity.



There are no springs on the inlet valve.

If you study the bottom of the rad cap, you'll discover either:
1) a round, thin rubber flap smaller than a dime, or
2) a wiggly post with a plastic disc on the end of it.

These are the inlet valves. It takes /next to/ zero negative pressure for
the rubber flap type to allow coolant back into the rad, and /definitely/
zero for the wiggly post type, which is always open until pressure shuts
it.

This assumes, of course, that both types are CLEAN. Goop and crud will plug
up the inlet and prevent free flow of coolant back to the rad.

This futher assumes you're using the correct OEM ND caps. If you've got
aftermarket crap, all bets are off as to how they work.

--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Re: Coolant Vanishing: different direction Coefficient_of_thermal_expansion
 

On Feb 25, 6:35 pm, Jeff <kidsdoc2...@hotmail.com> wrote:
> z wrote:
> > On Feb 21, 7:44 pm, Grumpy AuContraire <Gru...@ExtraGrumpyville.com>
> > wrote:
> >> Um, I said "boiling point" as a yardstick that is subject to change
> >> depending on how much pressure the liquid is subject to at the time.
>
> > of course, the coolant at operating temp is quite a bit above the
> > "boiling point" of 212 degrees, that's why it's pressurized.
>
> Actually, the thermostat on most cars is below 212 F. And the boiling
> point is above 212 with the antifreeze.
>
> > in other words, you've gone from about 500 fahrenheit degrees above
> > absolute zero, to about 700 degrees. as a first approximation, that's
> > gonna see a 40% expansion. i hope your hoses don't expand that much.
>
> It's actually going to be about 4% from O to 80 c (about 180 F).
>
> http://www.simetric.co.uk/si_water.htm
>
> Coolant will expand by a different amount, because it has antifreeze and
> other additives in it.
>
> Solids don't increase by 40% in volume from -40 F to 212 F. Why would
> you think water would?
>
> Jeff

wow. i stand corrected. my "estimate" obviously didn't include the
zero temp term,
i.e. if volume = A +B(absolutetemp) I was estimating that A = 0, which
obviously it doesn't.