I have an overheating condition with my Accord that I've been working
with for about a month now.
So far my parts list consists of:
1)Thermostat and hoses
3)Temperature switch A ( Water outlet housing )
4)Gauge temperature sender
5)Timing belt and water pump (1 year ago as of Feb 22 from the
Around town car is fine (temp gauge reads around halfway mark),
Thermostat opens as I can feel the top hose is hot. On highway gauge
climbs to around the 3/4 mark about 1/4 away from hot. Turn heater on
to bleed off excess heat and everything settles down until temp goes
I have done a meat thermometer test with the cap off, and the temp
goes up to 195 and levels off, with the gauge showing about halfway. I
turned the A/C on and the fans do not automatically turn on, they wait
about a minute or two before coming on. After parking the car and
turning it off, the fan comes on about 3 minutes after the car is
parked at normal operating temperature. I am not losing any coolant,
and nothing is mixing with the oil. I don't have any smoke other than
normal cold morning exhaust. I'm going to have the compression checked
just in case, but this really doesn't seem to be a head gasket or head
Anybody have any ideas?
look for bubbles in the expansion bottle. if you have any, it's
definitely head gasket. you'll see them at idle when the motor is at
full working temperature. traditional symptoms of water in the oil are
rare in hondas because of the wet cylinder liner configuration - any gas
leaking from the cylinders can only go into the coolant unless the head
regarding repair, are you planning on doing the work yourself? if so,
the math works, but if you're having it done by a shop, examine the
economics of simply replacing the engine with a used low mileage
japanese import engine. head gasket repair takes hours and is very
labor intensive. shops also routinely skim heads, which i personally
don't approve of unless there's a definite head warping problem.
email@example.com wrote in news:1172925865.592113.240130@
If the car begins to overheat when the engine is operating at elevated
speeds, there is a problem with heat being shed.
What coolant are you using? I wonder if your block and/or rad is silted up
and not allowing sufficient fluid flow.
How old is the radiator, and what brand is it? If you have an automatic, is
the rad a dual-core or single-core?
It's a brand new radiator from Advance, the motor is low mileage by
Honda standards (85,000). Since the fans don't come on with the A/C
I'm leaning towards it being either :
A) The fan timer ( I think I've found where it is in the car , but I'm
not sure exactly)
B)A wiring problem between the switch and the fan motor.
But since neither of the fans are coming on with the A/C it's
screaming to me that it's the timer.
P.S.: I swapped the power window relay with the Fan relay on the under-
hood fuse box, and no change.
you're barking up the wrong tree dude. if the car overheats when you're
on the freeway, it's /not/ the fans. freeway airflow vastly exceeds
fan-induced airflow. especially this time of year.
check for gotchas like newspaper stuck to the a/c condenser, but mainly,
look into the head gasket. you only need to over-heat the motor once
[say a crack in the old radiator] and differential thermal expansion can
break the seal. from that point on, it's going to leak slowly, which
you won't notice, then faster, until you do notice. overheating at
freeway speed is one of those symptoms.
This is NOT your problem. Fans are there to force airflow through the heat
exchangers at IDLE. At speed they are neither used nor needed.
You have a problem with fluid flow through the cores or through the block.
You should also verify the actual temperature with an infrared thermometer,
just to be certain it isn't the gauge misleading you.
Did you use an OEM thermostat? Just because the upper hose gets hot doesn't
mean the thermostat has opened, or has opened enough.
When the car is beginning to overheat, feel the rad all over with your
hand. Is it equally hot all over, or are there cooler spots?
Are you keeping the reservoir filled to the -MAX- mark (per the manual)?
It's one of the best ways to really figure out what's happening. If you
don't keep enough coolant in the reservoir the temp sensors can end up
high-n-dry when the thermostat opens and then the fan won't run when you
come off the highway.
It's also a good way to tell if you're USING coolant, either to displace
air or through leakage. That's why the manual tells you to make sure to
fill the reservoir any time you change the coolant or have work
performed on the system. It just makes sense to keep some reserve in the
My coolant stays at max summer and winter, by itself. It's a 'peace of
mind' kind of thing.
It is right smack dab between the Min and Max mark, it never runs any
lower, or higher.
I also ran it up to temp and turned the A/C on a little while ago and
let it run for about 10 minutes. The temp never went up past half on
the gauge (should be around 195 degrees). And neither of the fans came
on. I unplugged the A switch (the one that controls the radiator fan)
and checked it for continuity with my volt meter it showed a constant
flow across the terminals of around 11.5 volts. Noting that the upper
hose is hot, and the bottom hose is pressurized, this tells me that
the water pump is flowing correctly, the thermostat is open, and the
switch on the outlet housing has continuity. It's looking more and
more like the timer is bad.
On Mar 3, 9:40 am, firstname.lastname@example.org wrote:
Another one I just tried was jumpering the connections across the
harness that plugs into A switch. by theory, and advice, this should
have made the fan come on. The fan did not start. I then used my handy
old volt meter to check and I was getting 13.5 VDC across the harness
which tells me the circuit is powered up. The relay is good, as I
checked it by swapping it with the power window relay right next to it
and the power windows still work. It's either got to be the timer, the
motor, or the wiring.
On Mar 3, 9:53 am, email@example.com wrote:
Tegger, I used a Stant thermostat from Advance and installed it at the
same time as the radiator about 3 weeks ago.
The dealership said I was getting proper coolant flow through the
block as they checked out the water pump under warranty. The reason I
am suspicious about the radiator fans not coming on when the A/C is
engaged is I have been told by several people that the fans should
come on with the A/C.
ok, now we're getting there. use a honda thermostat. yes, the
aftermarket "should" be ok, but it isn't. make sure it's fitted
correctly too. right way up, right way out. forget the fans in your
diagnostics. you'll need to fix them, but they're not the cause of the
Turns out it was a brand new junk thermostat from Advance auto parts.
Installed correctly and everything. We used a buddy of mine's IR temp
gauge and noticed that the temp was 195 on the engine side of the
thermostat, and 120 on the hose side. BINGO!!! no coolant flow.
Thanks for the input.
I learned my lesson with my old Volvos, the first cars I had in a while that
had temperature guages. Aftermarket thermostats, mostly Stants, were all
over the place. Some were too hot, most too cold, and nearly all of them
wandered up and down the temperature scale at will. The first time I used a
genuine OEM thermostat it was like magic.
On Sun, 4 Mar 2007 11:35:00 -0700, "Michael Pardee"
I don't get it. If it's so well known that aftermarket thermostats are
crap (I had the same problem once, replaced the thermostat and the
problem remained), isn't it time that they got sued? Car manufacturers
with bad parts have to do recalls.
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