Cracked Block Probability

[Williams]

I've heard a lot about not putting cold water in a hot engine, but as
with most advice it's vague. Could someone with real experience of
cracked blocks etc tell me just how cold or hot they have to be to
almost ensure damage, as opposed to "run the risk of damage."
Also I hear that if there is an otherwise dangerous temperature
difference, the engine should be run to circulate the water to heat it
to avoid trouble. I would have thought it best to not do that because
that would get the water into the engine quicker. Wouldn't it be
better to let it sit in the radiator for a while to warm?
Thanks.

[C. E. White]

I think you are very unlikely to crack a block by pouring cold water on a
hot block. The blocks just are not that hot. Think about this - Cast iron
exhaust headers are much hotter than the blcok ever will be. Yet, how
often are they cracked when you drive through a deep puddle and splash
water all over the exhaust manifold?

Ed

[Lon Stowell]

Roughly 12/22/03 06:05, Williams's monkeys randomly typed:

> I've heard a lot about not putting cold water in a hot engine, but as
> with most advice it's vague. Could someone with real experience of
> cracked blocks etc tell me just how cold or hot they have to be to
> almost ensure damage, as opposed to "run the risk of damage."

Perhaps if you have an engine that is totally devoid of water
and is in an engine damaging state of overheat perhaps you could damage
the engine by adding near frozen water to the radiator.

Biggest risk in attempting to add water to a hot engine is
steam burns when you open the radiator cap... since pretty much
all current engines run with pressurized systems.

> Also I hear that if there is an otherwise dangerous temperature
> difference, the engine should be run to circulate the water to heat it
> to avoid trouble. I would have thought it best to not do that because
> that would get the water into the engine quicker. Wouldn't it be
> better to let it sit in the radiator for a while to warm?

If an engine is overheated, best way to add water is to first
pour it onto the radiator core to cool that down, ideally with the
engine running. If that works, run the engine a while to cool off
any hot spots, then shut the engine down and allow it to cool so
the radiator can be safely opened.

Then add water only in an emergency, as the engine would really
prefer a good drink of antifreeze/water mix.

If you do add water [or even mixed antifreeze] it won't hurt anything
to do it with the engine running, may even help get rid of water
bubbles. However it takes a while as when the water is colder than
the thermostat temperature, the thermostat will close and pretty
much stop circulation of the water from the radiator until the
temp goes high enough to open the 'stat again. With the cap off
you can make sure water is circulating properly, look for air
bubbles, etc. as you refill. Then put the cap on and make sure
the overflow bottle is clean and full as thats where some engines
have a coolant level warning sensor.

I suppose if there were a defective casting, the thermal shock
of really cold water in a hot engine could damage it... if it
gets much cold water into the engine before the thermostat
closes.

--
Fan of the dumbest team in America.

[Williams]

Thanks for the sensible reply Lon.
You make it sound like an urban myth, so where are all these people
who supposedly crack their blocks, I'm hoping to hear from them.

[Robert Hancock]

Apparently, one of the durability tests GM did on their new Ecotec 2.2L
engine was a thermal cycle test, where they ran the engine up to normal
operating temperature and then flushed it with ice-cold coolant. The engine
was required to survive this being repeated continuously for 1000 hours.

So, I would say the chances of most engines being damaged from this are
pretty low..

--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hanc...@nospamshaw.ca
Home Page: http://www.roberthancock.com/

"Williams" <bar...@ozemail.com.au> wrote in message
news:DTCFb.238$VJ3....@nnrp1.ozemail.com.au...

[Bob S.]

>
> Biggest risk in attempting to add water to a hot engine is
> steam burns when you open the radiator cap... since pretty much
> all current engines run with pressurized systems.
>

I have an older Chev pickup. It developed a leak and ran completely
dry while driving it. I removed the radiator cap with a towel over it
and there was no steam at all. I let it set for about 5 minutes and
then tried adding water into the radiator. It immediately turned to a
huge amount of steam and blew super hot water back onto my arm. (lucky
I had a jacket on).
The point being that care taken when opening the radiator cap should
also extend to the refilling process.

Bob

[Williams]

Thanks for the replies.
Is not even one person going to tell of a cracked block? Is it just an
urban myth?

[JazzMan]

Not everyone that's ever poured cold water into a hot engine
reads this newsgroup, or even has internet access for that
matter. The internet's big, but it's not that big.

The concensus is that it's a bad idea, but you need to decide
for yourself whether you agree or not.

JazzMan
--
**********************************************************
Please reply to jsavage"at"airmail.net.
Curse those darned bulk e-mailers!
**********************************************************
"Rats and roaches live by competition under the laws of
supply and demand. It is the privilege of human beings to
live under the laws of justice and mercy." - Wendell Berry
**********************************************************

[L0nD0t.$t0we11]

Roughly 1/5/04 05:16, Williams's monkeys randomly typed:

> Thanks for the replies.
> Is not even one person going to tell of a cracked block? Is it just an
> urban myth?
>

I don't think anyone is saying that it couldn't happen, just that
nobody has had it happen to them, their acquaintances, etc. etc.
and further that it is bloody freaking unlikely under reasonable
circumstances. Granted, some folks shouldn't be allowed near
anything mechanical, which is why it is possible it could have
happened.

[Tibur Waltson]

>"Lon Stowell" <LonDot....@ComcastPeriod.Net> wrote in message

> If an engine is overheated, best way to add water is to first
> pour it onto the radiator core to cool that down, ideally with the
> engine running. If that works, run the engine a while to cool off
> any hot spots, then shut the engine down and allow it to cool so

> the radiator can be safely opened. <snip>

>
> Then add water only in an emergency, as the engine would really
> prefer a good drink of antifreeze/water mix.

I'd avoid adding water until the motor drops to operating tempurature,
with engine off. If it's enough to crack the block then the head is
probably first to go.

To the OP:
The only scenarios I seen with crack blocks are from trapped coolant
under the head bolts, connecting rods failure and adding extremely
cold water to an overheated block.

Tibur

[HLS]

Some blocks are easier to crack than others. (Some of them did it
naturally, with no abusive treatment.)

Often, if you overheat an engine moderately, especially one with aluminum
block or heads, you may find you have warpage. It is more common for the
head to warp, but
not impossible for the block to do it too.

You won't get enough steam pressure to crack a block, but you can crack them
with
shock.

Normally, if you haven't driven the vehicle into the depths of Hell, you can
play water over the radiator, with the engine running, and get a bit of
cooling...maybe enough to
get it under control with little damage. You must NOT run up and open the
radiator cap
on a car like this, unless you really didn't value that hand anyway.

If you have destroyed the main bearings, say goodnight Gracie. You might as
well shut it
off and let it cool naturally. It will need to see the engine doctor.

My uncle (may he rest in peace) used to tell me stories about borrowing a
family member's Model T, and running it out of water. He said that the
block was glowing red
hot when he realized what he had done (literary license or truth, I don't
know). He
said he got a bucket of water out of the river and drowned that engine with
it. The block
didn't crack. (I believe in those days Babbitt metal bearings were used,
and if so, a red hot condition would have certainly melted the Babbitt).
Cranked it up and drove off.

He was a fun guy, and his pictures had been taken off the post office
bulletin boards when I heard this story.

Bottom line...
If you get yourself in this condition, you have to determine quickly whether
to try to cool the radiator or shut her off. Above all, be safe.

[cliff...@gmail.com]

Hi, reading your post years later lol.

I have cracked a block by pouring cold water into a non running engine while it was hot (not just normal operating temperature)

I had refilled this engine hot multiple times before, while running, no problem..... This time I shut it off, waited for the pressure to go down to where I could remove the cap sort of safely, then pored water in,
- this time without starting.

I poured about half a gallon in, and I heard a loud pop. The engine block was cracked and the coolant ran into the cylinder. 3/10 would not do again.

I think the danger is higher with a cast iron block, but I'm not sure.

[synthi...@yahoo.com]

I won't remember the details clearly by my '70 chevy lost a "freeze plug" in the winter 'cuz my antifreeze measure was faulty. I do remember desperately pouring water in, that had ice in it. The miracle was somebody telling of a shop that would fix it. I drove, stopping every mile or so when it overheated and poured more water in. they fixed it just fine and I got to use it for some years after.

Now, "freeze plug" is not what it was designed as, it was a lucky accident from the block casting process.

Nils K. Hammer

[The Real Bev]

Takes me back...

Four months pregnant and one of mine blew. Yeah, like we need those in
SoCal. For a while I could use the car by filling it up at home,
driving to work, filling it up at work and driving home. Ultimately I
crawled under the 1950 Chevy and replaced the STEEL freeze plug with a
brass one. Fortunately only one went bad.

It would have killed GM to use brass in the first place? Do they still
use them at all?

--
Cheers, Bev
"By the time they had diminished from 50 to 8, the other
dwarves began to suspect 'Hungry.'" -Gary Larson

[Steve W.]

The Real Bev wrote:
> On 07/09/2020 05:38 AM, synthi...@yahoo.com wrote:
>> I won't remember the details clearly by my '70 chevy lost a "freeze
>> plug" in the winter 'cuz my antifreeze measure was faulty. I do
>> remember desperately pouring water in, that had ice in it. The
>> miracle was somebody telling of a shop that would fix it. I drove,
>> stopping every mile or so when it overheated and poured more water
>> in. they fixed it just fine and I got to use it for some years
>> after.
>>
>> Now, "freeze plug" is not what it was designed as, it was a lucky
>> accident from the block casting process.
>
> Takes me back...
>
> Four months pregnant and one of mine blew. Yeah, like we need those in
> SoCal. For a while I could use the car by filling it up at home,
> driving to work, filling it up at work and driving home. Ultimately I
> crawled under the 1950 Chevy and replaced the STEEL freeze plug with a
> brass one. Fortunately only one went bad.
>
> It would have killed GM to use brass in the first place? Do they still
> use them at all?
>

Yep, pretty much every engine still has core plugs in the block and
head(s). The only easy way to get the sand out of the water jacket
areas. The ones that don't have them are normally engines that use wet
sleeves like diesels and large engines that have hatches into the block.

--
Steve W.

[The Real Bev]

On 07/09/2020 12:30 PM, Steve W. wrote:
> The Real Bev wrote:
>> On 07/09/2020 05:38 AM, synthi...@yahoo.com wrote:
>>> I won't remember the details clearly by my '70 chevy lost a "freeze
>>> plug" in the winter 'cuz my antifreeze measure was faulty. I do
>>> remember desperately pouring water in, that had ice in it. The
>>> miracle was somebody telling of a shop that would fix it. I drove,
>>> stopping every mile or so when it overheated and poured more water
>>> in. they fixed it just fine and I got to use it for some years
>>> after.
>>>
>>> Now, "freeze plug" is not what it was designed as, it was a lucky
>>> accident from the block casting process.
>>
>> Takes me back...
>>
>> Four months pregnant and one of mine blew. Yeah, like we need those in
>> SoCal. For a while I could use the car by filling it up at home,
>> driving to work, filling it up at work and driving home. Ultimately I
>> crawled under the 1950 Chevy and replaced the STEEL freeze plug with a
>> brass one. Fortunately only one went bad.

I am informed that SOME cars have plugs at the other end of the block
such that you have to lift the engine to replace them. How evil is that?

>> It would have killed GM to use brass in the first place? Do they still
>> use them at all?
>
> Yep, pretty much every engine still has core plugs in the block and
> head(s). The only easy way to get the sand out of the water jacket
> areas. The ones that don't have them are normally engines that use wet
> sleeves like diesels and large engines that have hatches into the block.

For extremely difficult and time-consuming values of 'easy'. Where does
the sand come from and what does it do? We've been driving old cars
(1968-70) for a long time and if we have sand we sure don't know it!

--
Cheers, Bev
"The last thing you want is for somebody to commit suicide
before executing them."
-Gary Deland, former Utah director for corrections

[Scott Dorsey]

The block is sandcast, then some stuff on it is precision machined. It is
not just machined out of a solid billet. When you pop off the head cover,
you can see the rough surfaces that result from unfinished sand casting.

And when you sandcast, you have to get all the sand out because it is
abrasive. Even with pretty aggressive removal, there's usually still some
left that comes out during the break-in process.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Paul in Houston TX]

> For extremely difficult and time-consuming values of 'easy'.  Where does
> the sand come from and what does it do?  We've been driving old cars
> (1968-70) for a long time and if we have sand we sure don't know it!

This is a good video on engine block mfg:

https://www.youtube.com/watch?v=211Xkut0VGI

It looks like Goggle/youtube has found a way past all my ad blockers and
user agents. Hit Refresh one or more times to get past the ads.

[AMuzi]

Yep, pointless in SoCal but significant up nort'.

They're a necessary foible of the sandcasting process (my GM
aluminum engine doesn't have them) and do indeed prevent
total block loss if the operator neglects coolant mixture in
severe cold. I'm not at all sure that brass or steel plugs
would function or fail differently.

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

[Xeno]

I have worked on very large engines that have screwed in brass casting
plugs. They generally don't fail in terms of leakage or corrosion but
cost a lot more in the manufacturing process. They also won't
conveniently pop out in the case of the coolant freezing.

In general however, the standard variety welch plugs come in two forms,
dished and domed. They are made of plated steel but can be had in brass
at a higher cost. Use an appropriate coolant and the factory OEM units
should last out the engine at least until rebuild time where it would be
prudent to replace them.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)