Any harm to drive around w/o a thermostat??
Charlie Cho
ago, my car was overheating because the thermostat wasn't working properly.
So, I've removed it and have been driving around without it ever since.
The engine runs a lot cooler and also takes longer to warm up. What I
was told was that the thermostat is used to restrict the flow of the
coolant into the engine to help it warm up quicker. Is there any harm
in driving around without a thermostat?
Charlie Cho
Hewlett-Packard
Cupertino, CA
cha...@hpindda.hp.com
Dan Dunphy
contaminants. your engine will wear out very quickly.
Replace the thermostat immediately.
Chris Prael
> Can anyone tell me what the purpose of the thermostat is? Several months
As you were told else where, and mention below, the purpose of the
thermostat is to warm the engine more quickly.
> ago, my car was overheating because the thermostat wasn't working properly.
> So, I've removed it and have been driving around without it ever since.
> The engine runs a lot cooler and also takes longer to warm up. What I
> was told was that the thermostat is used to restrict the flow of the
> coolant into the engine to help it warm up quicker. Is there any harm
> in driving around without a thermostat?
It depends on how long you plan to keep the car. 95% of all engine wear
happens during warmup. This is because the clearances in the engine are
as specification ONLY when the engine is warm. When the engine is cold,
the clearences are off. As the engine warms, different parts expand at
different rates, making the clearences even messier for short periods.
Extending the amount of time that the engine is running cooler than it
was designed to run, makes the engine wear out faster.
Chris Prael
Chuck Fry
(Charlie Cho) writes:
>Can anyone tell me what the purpose of the thermostat is? Several months
>ago, my car was overheating because the thermostat wasn't working properly.
>So, I've removed it and have been driving around without it ever since.
>The engine runs a lot cooler and also takes longer to warm up. What I
>was told was that the thermostat is used to restrict the flow of the
>coolant into the engine to help it warm up quicker. Is there any harm
>in driving around without a thermostat?
Yes. As you noted, it takes the engine a lot longer to warm up, and
when it finally does get warm it runs cooler. This is a problem
because:
(1) Engine oil works best when it is warm, around 180-200 degrees F
(roughly 85-95 degrees C, I think). At lower temperatures it doesn't
lubricate as well, and the increased friction will reduce power and
increase wear.
(2) The fuel will not atomize and evaporate properly, causing less
efficient burning. This means lower gas mileage and more pollutants
coming out the tailpipe. Since this is a California car, removing the
thermostat might be ILLEGAL on the basis of increased pollution.
(3) Just speculating here, but I think since the engine's temperature
will vary radically with load and speed, the increased rate of thermal
cycling might cause thermal fatigue much sooner.
Is this enough reason to reinstall a $5-10 part? I think so. If the
thermostat wasn't working in the first place, you should have replaced
it rather than removed it. If installing a working T-stat causes the
car to overheat, you have other cooling problems that should be fixed
pronto.
-- Chuck Fry Chu...@Charon.ARC.NASA.GOV ...!ames!ptolemy!chucko
Jon Lusky
decreased performance and economy. Heater won't work worth a damn in the
winter.
Ron Phillips
Several months
Basically,
1. When the thermostat's rated temperature is reached, the thermostat
opens and allows coolant to enter the chambers (prevent overheating)
2. This "new" coolant passing through the thermostat reduces the
temperature to below the rated temperature causing the themostat
to close and, in turn, "traps" the coolant in the radiator where
air flow cools it down.
Removing the thermostat can be *very* hazardous to your engines health.
Without a thermostat, the coolant is continuously flowing through the
engine chambers, resulting in a gradual, continuous heating of the coolant
and build-up of coolant system pressure.
.
Eventually, the coolant can exceed the engine temperature specifications
and coolant system pressure can be exceeded. Everything from "bursting"
hoses to Head gasket and/or head warpage problems from such occurances are
*not* uncommon!
--------------------------------------------------------------------------
Ron Phillips UUCP: {uunet, nsc, pyramid, atari}!daisy!ronp
Daisy/Cadnetix, Inc. [ro...@daisy.UUCP]
222 Caspian Drive VOICE: (408) 747-7980
Sunnyvale, CA 94089 FAX: (408) 747-7572
--------------------------------------------------------------------------
Geoff Miller
In article <4...@daisy.UUCP> ro...@daisy.UUCP (Ron Phillips) writes:
>Removing the thermostat can be *very* hazardous to your engines health.
>Without a thermostat, the coolant is continuously flowing through the
>engine chambers, resulting in a gradual, continuous heating of the coolant
>and build-up of coolant system pressure.
But with the thermostat removed, the coolant is able to circulate unimpeded
between the engine and the radiator -- so how could there be a "gradual,
continuous heating" of the coolant? You make it sound as though the result
of removing the thermostat is isolation of the radiator from the coolant in
the engine, when in actuality the exact opposite happens: the coolant has
unrestricted access to the radiator, which prevents in the engine from
attaining the proper temperature.
Geoff
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Geoff Miller + + + + + + + + Sun Microsystems
geo...@purplehaze.sun.com + + + + + + + + Milpitas, California
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Walter A. Koziarz
Unless your engine is a 6BT-5.9 Cummins Turbo Diesel; in which case the 'path
of least resistance' for the water to flow is right back to the block, i.e.
bypassing the radiator. In this case, the engine will obviously overheat.
Replace the thermostat immediately.
Walt K.
Alan Hepburn
+Basically,
+
+ 1. When the thermostat's rated temperature is reached, the thermostat
+ opens and allows coolant to enter the chambers (prevent overheating)
+
+ 2. This "new" coolant passing through the thermostat reduces the
+ temperature to below the rated temperature causing the themostat
+ to close and, in turn, "traps" the coolant in the radiator where
+ air flow cools it down.
+
+Removing the thermostat can be *very* hazardous to your engines health.
+Without a thermostat, the coolant is continuously flowing through the
+engine chambers, resulting in a gradual, continuous heating of the coolant
+and build-up of coolant system pressure.
+.
+Eventually, the coolant can exceed the engine temperature specifications
+and coolant system pressure can be exceeded. Everything from "bursting"
+hoses to Head gasket and/or head warpage problems from such occurances are
+*not* uncommon!
+
+--------------------------------------------------------------------------
+Ron Phillips UUCP: {uunet, nsc, pyramid, atari}!daisy!ronp
+Daisy/Cadnetix, Inc. [ro...@daisy.UUCP]
+222 Caspian Drive VOICE: (408) 747-7980
+Sunnyvale, CA 94089 FAX: (408) 747-7572
+--------------------------------------------------------------------------
This is direct contrast to personal experience. Back in my younger
days (long, long ago in a galaxy far, far away?) I drove my car, a
1957 Mercury Commuter station wagon (remember them?) from San Diego
to San Jose nonstop (except for gas stops) without a thermostat
installed and the temp guage never came up off the cold peg. With
no thermostat, the coolant is constantly circulating through the
radiator and the engine cannot heat the coolant up enough to raise
the pressure a significant amount. Even idling for extended periods
with no thermostat will not overheat the engine. With a cold engine,
your choke (assuming automatic choke here) will not open and you will
be running quite rich. The heat riser on the exhaust, if it's working
will not open and you will be restricting the flow of gases there.
Others have already mentioned the fact that the oil will never reach
operating temperature.
--
Alan Hepburn "The exact contrary of what is generally
mail: al...@spitfire.nsc.com believed is often the truth."
- Jean de La Bruyere
Ken Kastella
Basically,
I think you have the coolant flow backwards. When the engine heats up, the
thermostat opens allowing coolant to flow into the radiator. The cooled
coolant then flows back into the engine block cooling the engine and also
cooling the thermostat which then closes - at least partially. Any problems
running without a thermostat are those associated with running an engine at
too low a temperature, not too high. At least that is true if you have
installed the thermostat correctly!
Ken Kastella
John E Upham
> In article <452...@hpindda.cup.hp.com> cha...@hpindda.cup.hp.com (Charlie Cho) writes:
>>Can anyone tell me what the purpose of the thermostat is?
> Several months
>
> Basically,
>
> 1. When the thermostat's rated temperature is reached, the thermostat
> opens and allows coolant to enter the chambers (prevent overheating)
>
> 2. This "new" coolant passing through the thermostat reduces the
> temperature to below the rated temperature causing the themostat
> to close and, in turn, "traps" the coolant in the radiator where
> air flow cools it down.
>
> Removing the thermostat can be *very* hazardous to your engines health.
> Without a thermostat, the coolant is continuously flowing through the
> engine chambers, resulting in a gradual, continuous heating of the coolant
> and build-up of coolant system pressure.
> .
> Eventually, the coolant can exceed the engine temperature specifications
> and coolant system pressure can be exceeded. Everything from "bursting"
> hoses to Head gasket and/or head warpage problems from such occurances are
> *not* uncommon!
I must be going mad ! I don't understand this reply at all. I think
this person assumes a vehicle coolant thermostat functions like the
one in the electric kettle, i.e. with no thermostat the kettle keeps
heating until something blows ups !
I think a bit of pratical knowledge rather than theoretical guessing is
required. The engines thermostat when below its rated temperature (say
90 Celcius) is closed and coolant passes only around the block and
inlet manifold and NOT the radiator. As the engine runs the coolant
heats up and eventually reaches 90 C and will open the thermostat. This
will allow coolant to now pass around the radiator which will dissapate
heat via convection (mainly) so the coolant temperature leaving the rad
will be lower than entering (wow !) hence COOLING. The problem with
removing the stat is the cooling occurs all the time and apart from
running in the sahara desert this is a problem since the engine fails
to reach proper operating temperature.
As an expt. I ran my engine with no thermostat and despite sitting
idling for ages it wouldn't warm up. Now even when the stat is in place
and open it still provides significant resistance to flow which
moderates the cooling rate. I hope the person above doesn't work for
as a mechanic !
John Upham, (Chemical Physics Ph.D)
University of Sussex, Brighton, UK.
Email: kapn1%cluster.s...@uk.ac (BITnet)
ka...@uk.ac.susx.cluster (Janet)
johnu%syma.su...@uk.ac (BITnet)
jo...@uk.ac.susx.syma (Janet)
Tel: +44 273 680500 (eve)
Tel: +44 273 678332 (day)
Fax: +44 273 671966
"I've counted them all out and I've counted them all back"
Murray Walker (?) commentating on the restart at F1 WC, Spa, 1990
Bob Haar CS50
|> In article <452...@hpindda.cup.hp.com> cha...@hpindda.cup.hp.com
(Charlie Cho) writes:
|> >Can anyone tell me what the purpose of the thermostat is?
|>
|> opens and allows coolant to enter the chambers (prevent overheating)
|> 2. This "new" coolant passing through the thermostat reduces the
|> temperature to below the rated temperature causing the themostat
|> to close and, in turn, "traps" the coolant in the radiator where
|> air flow cools it down.
so far, so good....
|> Removing the thermostat can be *very* hazardous to your engines health.
|> Without a thermostat, the coolant is continuously flowing through the
|> engine chambers, resulting in a gradual, continuous heating of the coolant
|> and build-up of coolant system pressure.
yes, but for the wrong reasons....
|> Eventually, the coolant can exceed the engine temperature specifications
|> and coolant system pressure can be exceeded.
wrong! The problem is that the engine and coolant will take much longer
to warm up, thus increasing wear and pollution while decreasing
gas mileage.
When a car engine reaches a steady state operating temperature (say after
ten minutes of driving), the thermostat is typically open and stays that way.
On some cars with high temp thermostats, you might get only partial
opening. The steady state temperature is determined by the heat produced by
engine compared to the heat losses to the environment. With the
thermostat open or removed, the heat losses include that from the
radiator. This results in a lower temperature than if the thermostat is
closed.
Bob Haar CSNET: HA...@GMR.COM UUCP: uunet!edsews!rphroy!rcsrlh!rhaar
Computer Science Dept., G.M. Research Laboratories
DISCLAIMER: Unless indicated otherwise, everything in this note is
personal opinion, not an official statement of General Motors Corp.
Ron Phillips
>
<<< I deleted by article about not having thermostat, coolant temperature
& pressure gradually rising to exceed specifications & causing burst
hoses, blown head gasket, warped heads & etc. >>>
>This is direct contrast to personal experience.
On the next 85+ degree summer day, remove your thermostat and drive in stop &
go traffic for an hour or so. I think doing so will result in sufficient
pressure/heat build-up to re-enforce my statement.
--------------------------------------------------------------------------
Ron Phillips UUCP: {uunet, nsc, pyramid, atari}!daisy!ronp
Daisy/Cadnetix, Inc. [ro...@daisy.UUCP]
222 Caspian Drive VOICE: (408) 747-7980
Sunnyvale, CA 94089 FAX: (408) 747-7572
--------------------------------------------------------------------------
Ron Phillips
>
>But with the thermostat removed, the coolant is able to circulate unimpeded
>between the engine and the radiator -- so how could there be a "gradual,
>continuous heating" of the coolant? You make it sound as though the result
>of removing the thermostat is isolation of the radiator from the coolant in
>the engine, when in actuality the exact opposite happens: the coolant has
>unrestricted access to the radiator, which prevents in the engine from
>attaining the proper temperature.
>
ture. However, try it on a hot summer day (85+ degrees) in stop and go
traffic for an hour or so. The air flow past the radiator is insufficient
(and often heated by the road surface) and the coolant doesn't remain in
the radiator long enough to perform any significant cooling.
This is *not* an uncommon problem with thermostats stuck in the open
position.
Ron Phillips
>
>I think you have the coolant flow backwards.
Six of one, half dozen of the other ... I didn't intend to get into the
technical aspect of coolant flow direction & etc. ... I merely wanted to
convey the concept that heated coolant is passed to the radiator so it can
be trapped and cooled and cooled coolant is passed from the radiator to the
engine chambers.
>Any problems
>running without a thermostat are those associated with running an engine at
>too low a temperature, not too high. At least that is true if you have
>installed the thermostat correctly!
>
This is true at freeway speed where sufficient air flow can be maintained to
provide cooling in the short amount of time the coolant takes to pass through
the radiator.
However, remove your thermostat and drive on an 85+ degree summer day in
stop-and-go commute traffic for an hour or so. The minimal air flow (often
heated up by road temperature and/or exhaust from the vehicle in front of
you) coupled with the short amount of time the coolant remains in the radiator
*will* result in increased temperature and/or pressure build-up. This is
a common occurance when thermostats get stuck open and cost *many* people
lots of dollars to fix.
Joe Matkowski <matkowsk>
Hey guys, aren't we forgetting one of the primary functions of the
thermostat?!? To perhaps provide a little heat for the occupants
in the vehicle. I made the mistake of removing one without replacing
it one time. Forget about what happens to the car, it really sucked
to drive home in 20 degrees with both windows rolled down at 65 MPH
because the damn windshield kept fogging up!
** Icepick **
"I have sworn upon the altar of God, eternal hostility
against every form of tyranny over the mind of man" --- Thomas Jefferson
********************************* DISCLAIMER **********************************
My opinions expressed here are just that, MINE! My employer does not support
my views, flames, rebuttals, or ramblings in any way shape or form. They are
thus exempt from liability of my statements!
*******************************************************************************
Thomas Tornblom
Can anyone tell me what the purpose of the thermostat is? Several months
ago, my car was overheating because the thermostat wasn't working properly.
So, I've removed it and have been driving around without it ever since.
The engine runs a lot cooler and also takes longer to warm up. What I
was told was that the thermostat is used to restrict the flow of the
coolant into the engine to help it warm up quicker. Is there any harm
in driving around without a thermostat?
Besides all the other relevant comments on engine wear etc there are other
problems on many cars.
I once had a -81 Chevy van with a broken thermostat, it didn't keep the
engine temperature high enough to engage the lock-up in the tranny.
The lock-up is electrically controlled via a vacuum controlled switch.
This switch gets its vacuum from the carburettor via a thermo controlled
valve. This valve never opened before replacing the thermostat.
Lots of emission control equipment are also controlled this way, EGR valves
etc.
--
Real life: Thomas Tornblom Email: tho...@uppsala.telesoft.se
Snail mail: Telesoft Uppsala AB Phone: +46 18 189406
Box 1218 Fax: +46 18 132039
S - 751 42 Uppsala, Sweden
Ron Phillips
>
>When a car engine reaches a steady state operating temperature (say after
>ten minutes of driving), the thermostat is typically open and stays that way.
No! When the thermostat reaches its rated temperature, it opens. The heated
coolant from the engine chambers passes to the radiator. "Cooled" coolant from
the radiator passes to the engine chambers and through the thermostat. When
this "cooled" coolant succeeds in lowering the bi-metal thermocouple in the
thermostat below temperature, the thermostat acts as a "valve" and closes. In
turn, this traps the "heated" coolant in the radiator. If all is working
properly, the "heated" coolant "in-radiator-time" and the amount of air-flow
through the radiator "fins" will sufficiently allow heat transfer from the
coolant to the metal of the radiator ("cooling" isn't added ... instead,
"heat" is removed). Under proper operation, your engine operating temperature
actually fluctuates something like +/- 10 degrees with the opening closing of
the thermostat.
>On some cars with high temp thermostats, you might get only partial
>opening. The steady state temperature is determined by the heat produced by
>engine compared to the heat losses to the environment. With the
>thermostat open or removed, the heat losses include that from the
>radiator. This results in a lower temperature than if the thermostat is
>closed.
>
Only if coolant "in-radiator-time" and air-flow are sufficient to maintain a
sufficient "heat transfer" rate between the coolant and the metal of the
radiator. If coolant "in-radiator-time" or air-flow are insufficient to
maintain a "cooling" effect, the temperature of the coolant will gradually
rise. If lack of radiator cap maintenance (deterioration/rubber degradation
& etc.) results in radiator cap pressure relief exceeding specifications,
internal pressure *can* burst hoses, gaskets & warp heads. (Take your
thermostat out, drive around on an 85+ degree day for about a half-hour
as if you are stuck in heavy commute traffic. Then, try to take your car
up climb in heavy traffic (4000 feet altitude change in 1/2 hour). Want to
bet on whether or not the "idiot" light comes on?