Overheating Civic..Ive treid it all
SUlClDE
Hey whats up...k her goes...I have an 85 civic, I replaced the thermostat, fan
switch, fan switch relay, hose etc. Car runs hot only when in traffic. It
warms up fine, plenty of power from the eng. Catalytic converter is new,
exhaust is new. Doesnt burn ANY oil etc. The fan turns on and stuff. When I
changed the thermostat, I bled the air by running the car with the radiator cap
off and squeezing the upper radiator house over and over till no more bubbles
showed up, and no more coolant would fit into the system. NOW is that the
right way?..They really isnt a bleed bolt on that housing...i think. All the
service manuals Ive read say a lean mixture could be at fault (did a propane
test..seems ok) Would the ignition timing affect it?...havent reallly ever
checked it...engine doesnt deisel or hesitate so i never really bothered. one
interesting note though..SOMETIMES .I do hear some water rushing into the
heater core when I first start the car....VERY VERY VERY faint , barely
audible... but If i listen hard enough...I can hear it sometimes. Hell I even
washed the radiator fins and picked out all the bugs and stones. My only
choices are the drivebelt tensions(not likely), air in the system (maybe), and
the last thing is the catalytic converter + the exhaust manifold could be
heating up the friigin radiator water cause its pretty damn close to it (highly
unlikely...but Ill fabricate a better heat shield anyway)
Id appreciate your help
Thanx guys!
Alex Chau
I think there may be two other places you want to check: 1) Radiator cap,
it has to be in good condition to maintain a pressurize system. 2) Rust
inside the radiator: It will reduce the efficiency of the heat exchange to
the outside. When the car is in traffic with slower or little airflow, it
may not get the heat out so efficiently that the coolant temp rise.
I personally tried a Prestone radiator cleaner that mixed only with water
and can run for about 6-10 hours (can't remember exactly the name of it) and
I was surprised that the water drained out with much darker rusty residue.
My engine runs a little cooler then.
SUlClDE wrote in message
<199805100519...@ladder03.news.aol.com>...
Rob Relf
You don't say how far the temp gauge goes up when in traffic (2/3 to 3/4
scale at most is tolerable). The usual reason for overheating on this car
when everything should be ok is a leaking head gasket allowing bubbles into
the cooling passages in the cylinder head which causes poor cooling (and
rushing sounds in the heater). With the engine cool, remove the coil wire
from the cap and the cap from the radiator. Make sure the cooling system is
full and then crank the engine while holding the throttle wide open. If the
coolant rises up in the radiator neck at all, the head gasket is leaking.
Rob
Greg Husemeier
Try taking the top hose of the radiator off (the one that goes to the engine
block from the top side of the motor), at the radiator, and pour coolant
directly into the engine through this hose. I replaced a lot of air with
coolant on my 92 Civic Si using this method the last time I replaced my
thermostat (for preventative maintenance).
Greg
John Hahnenfeld
The best thing you can do is to remove the thermostat completely.
The thermostat is restricting the flow of water into the engine. I had a
86 honda accord with the same problem. The removal of the thermostat did
the job. I know it doesn't sound like a good idea removing parts from you
car but in this case is a good idea. I always remove the thermostat on my
86 accord on the summer and put it back on the winter. If the temperature
where you live never goes below 60 degrees fahranheit leave it off all
year round.
Steve Sheldon
sul...@aol.com (SUlClDE) writes:
>Hey whats up...k her goes...I have an 85 civic, I replaced the thermostat, fan
>switch, fan switch relay, hose etc. Car runs hot only when in traffic. It
>warms up fine, plenty of power from the eng. Catalytic converter is new,
>exhaust is new. Doesnt burn ANY oil etc. The fan turns on and stuff. When I
>changed the thermostat, I bled the air by running the car with the radiator cap
You have restricted flow within the cooling system.
On a car this old, you do tend to get a lot of buildup within the cooling
system.
First step would be to try flushing the system really well.
If that doesn't help you might try replacing the radiator. Although the
clogging could be somewhere else, the radiator is usually a first suspect
because it has smaller holes.
Gene Morrow
It could be a plugged radiator.
On 10 May 1998 05:19:27 GMT, sul...@aol.com (SUlClDE) wrote:
>Hey whats up...k her goes...I have an 85 civic, I replaced the thermostat, fan
>switch, fan switch relay, hose etc. Car runs hot only when in traffic.
Delete ".spam" from my E-Mail address
91CivicDX
Thinking with the right brain and typing with the left brain, SUlClDE conjured up in rec.autos.makers.honda:
:Hey whats up...k her goes...I have an 85 civic, I replaced the thermostat, fan
:switch, fan switch relay, hose etc. Car runs hot only when in traffic. It
:warms up fine, plenty of power from the eng. Catalytic converter is new,
:exhaust is new. Doesnt burn ANY oil etc. The fan turns on and stuff. When I
:changed the thermostat, I bled the air by running the car with the radiator cap
:showed up, and no more coolant would fit into the system. NOW is that the
:right way?..They really isnt a bleed bolt on that housing...i think. All the
There's a dull gray valve close to where the main rad hose meets the engine
block on my car.
:Thanx guys!
Good luck.
--
Alan
"Go juice yourself."--Andrea Toole
Mista Bone
NEVER and I mean ever run any engine without a thermostat in place for
any legnth of time, unless testing. The thermostat provides some
restriction so the coolant has time to absorb heat from hot metal
surfaces. This is a common V—8 trick that has to many overheated and
dead engines. MOROSO parts sell restrictors to put in place of
thermostat for this purpose, but might not fit any imports.
C. Tague aka. Mista Bone
"Baby won't you rock it tonight."
93 Honda Civic DX HB #17 DSP
Clarion, JBL, & MTX <Removed for racing
Neuspeed, Eibach, & BFG R1
Beauwolfe
SUlClDE wrote:
> Hey whats up...k her goes...I have an 85 civic, I replaced the thermostat, fan
> switch, fan switch relay, hose etc. Car runs hot only when in traffic.
Check your fan motor itself.
Beauwolfe
Mista Bone wrote:
> The thermostat provides some
> restriction so the coolant has time to absorb heat from hot metal
> surfaces.
Old wives tale.
spamno_...@ibm.net
Violates the laws of physics. Heat is kinetic energy of the molecules.
Heat transfer is instantaneous, as soon as the water molecules touch the
metal molecules. Like a billiard ball hitting another; how long does it
take for the energy to transfer? Could you bounce one ball off another
so fast the second one doesn't pick up any energy? No, energy transfer
is inherent in the contact, doesn't take any extra time. Faster you pump
the water through, faster you can move the heat.
To put it another way: if you increase the water flow, each ml of water
has less time to absorb the heat; but you are putting more water
through, by the exact same factor, so it cancels out. But heat transfer
depends on the temperature difference between the metal and the water;
the longer the water stays in there, the warmer it gets and the slower
the heat transfers. Speed the water up, the temp of the water stays
lower, the heat transfers faster.
>
> NEVER and I mean ever run any engine without a thermostat in place for
> restriction so the coolant has time to absorb heat from hot metal
Kevin McMurtrie
>Hey whats up...k her goes...I have an 85 civic, I replaced the thermostat, fan
>switch, fan switch relay, hose etc. Car runs hot only when in traffic. It
>warms up fine, plenty of power from the eng. Catalytic converter is new,
>exhaust is new. Doesnt burn ANY oil etc. The fan turns on and stuff. When I
>changed the thermostat, I bled the air by running the car with the radiator cap
- - -
Did you replace the cap? Old caps let the coolant out into the resevoir too easily so the system circulates steam bubles. They can also leak in air when the steam condenses. I had to replace the cap in my Tercel every year or all the coolant would blow out through the resevoir vent at high throttle.
The last thing to check is the idle speed. The car will overheat if it's wrong.
Mista Bone
If you pump the coolant too fast, It will absorb heat but will not give
up the heat to radiator enough too cool it. Then you have warmer than
normal coolant going back into engine, gaining more heat that is unable
to give up to radiator, continuing the cycle. There is a point where
fast coolant flow becomes TOO fast to be effiecient. Therefore causing
heat tranfer problems. Example, take a well designed home
heating/cooling system, block of 2/3 of the vents, and system looses
effiency because of increased flow that is too much. Read a couple of
articles by Smokey Yunich (sp?) and you will see what I mean.
Henri Helanto
crt...@webtv.net (Mista Bone) writes:
>If you pump the coolant too fast, It will absorb heat but will not give
>up the heat to radiator enough too cool it. Then you have warmer than
>normal coolant going back into engine, gaining more heat that is unable
>to give up to radiator, continuing the cycle. There is a point where
<snip>
Before this goes any further, I have to cut in:
Theoretically it _is_ possible for the coolant to flow 'too' fast,
but if that's the case the engine will run decisively _cooler_
than it would with slower flow. BUT, this all is purely academic
as the water pump would have to sap a large percentage of the
engine power in order to do that.
All in all, curing overheating problems is only a matter of:
-Sufficient flow of coolant (both speed and volume)
-Heat transfer from engine block and head to the coolant
-Heat transfer from coolant to outside air via radiator
(The thermostat is there to prevent the engine from running too
cool by restricting cooland flow)
If no other symptoms of engine overheating arise than the thermometer
needle staying in the red zone, replacing the sensor and maybe even
the gauge should suffice ;)
-Henri
--
# Henri Helanto ; he...@muncca.fi ; hhel...@cc.hut.fi #
# Nissan Skyline GT-R ; '71 Corvette LS-6 ; GMC Typhoon ; etc...#
CAUTION: Before engaging mouth make sure that the brain is in gear.
Rich Spear
Let me guess, you're not a heat transfer engineer.
You obviously don't understand the engineering principals behind a radiator,
water pump, thermostat and cooling system. This post is so wrong it's barely
worth commenting on, except that others may read it and believe it.
And your analogy is so far off base (removing restriction to increase volume
flow and lower velocity vs. restricting flow to increase velocity, causing
increased drag and lowered efficiency), it's amusing.
Mista Bone wrote:
> If you pump the coolant too fast, It will absorb heat but will not give
> up the heat to radiator enough too cool it. Then you have warmer than
> normal coolant going back into engine, gaining more heat that is unable
> to give up to radiator, continuing the cycle. There is a point where
SUlClDE
that just prevents the engine from warming up....driving a car on the highway
with the temp Guage is on C ...is not too cool.... arestrictive plate made FROM
the thermostat would be better..but why do it when the thermostat is there for
a reason....
spamno_...@ibm.net
Naw, same deal in reverse for the radiator: heat goes from the water to
the metal on contact. Doubling the flow (for instance) means twice as
much water flowing, but each ml delivers half as much heat so it cancels
out; but again, keeping the water in the radiator longer with slower
flow would cause the temps to come closer to equal and decrease heat
transfer.
Another analogy: have you ever said 'turn the fan down, the breeze is
too fast to cool me?'
Having said all that, it occurs to me that real life cooling vs. coolant
flow involves other things besides the actual heat transfer from the
water to the metal and vice versa. One thing that occurs to me is
cavitation; you can only put so much stress on water before the liquid
basically pulls apart and short lived bubbles appear, just from the
mechanical shear, not temperature. It's a big problem with superfast
outboard motor propellors, etc. Seems to me that would certainly screw
up the heat transfer. But I'm not an expert on this at all; I don't know
if turbulence in the cooling system could cause this, or if you could
crank the water pump fast enough to generate any cavitation, or if
removing the thermostat or other restrictions would lead into that
direction. Or if there are other factors I haven't thought of that might
cause cooling to fall off with no thermostat. But I'm pretty sure that
if there is such a falloff, it isn't due to reduced heat transfer from
the water flowing too fast.
Luis Miguel Pedroso
Quite true. If the flow increases, the heat transfer in every place will
increase as a consequence of the better transference of energy between the fluid
and the metal parts. On the other hand, the pressure drop will be higher.
Rich Spear wrote:
> Let me guess, you're not a heat transfer engineer.
>
> You obviously don't understand the engineering principals behind a radiator,
> water pump, thermostat and cooling system. This post is so wrong it's barely
> ...
Robert Snow
The thermostat is there for a reason. It allows the engine to warm up
quickly. This is good in the winter when you want to get comfy and good for
the engine which operates most efficiently at operating temperature.
Driving around with an engine that never warms up causes problems with fuel
mixture and emissions. Removing the thermostat is usually a last ditch
effort to compensate for some failure in the cooling system.