93 Accord overheating

I have a 93 Accord that began overheating this afternoon. I live in upstate
NY and the temperature outside is between 30 and 40 degrees. It seems to
overheat quickly while the car is sitting but, according to my daughter, the
temperature gauge comes back to the normal range while moving. I checked
the reservoir and it seemed to be very low....could not tell if it was empty
but I did see some liquid in it. I filled it up with a 50/50 mixture and
started the car (which was already warm). The temperature gauge rose pretty
quickly towards the red zone so I turned the car off. I can say that I
don't believe the two fans came on at all.

So...any ideas? What do I check? What causes the fans to turn on? Could
this simply be a defective thermostat? I guess I could check that pretty
easily. I believe the water pump was replaced when they replaced the timing
belt which was 30-40K ago.

Thank you for your help.

Bill

 

Okay...did a little more research on this issue as I have the service manual
for the car from Honda. It appears to me that it could be the main
thermostat, the ETC thermostat/switch that controls the fan, or the fan
itself? Would you agree? While the manual does tell you how to test the
thermostat, it does not tell you how to test the ETC switch. Anyone have
any idea how you test this. I would assume you could check resistance at
room temperature and at an elevated temperature? I was surprised that the
manual did not tell me how to troubleshoot this area of the car!

Thanks again!

Bill

 

Most cars have multiple ECT senders and switches, one ECT sender for the
temperature gauge, one ECT sender for the ECM and one ECT switch for the
radiator fan. The latter is a simple on/off type. Open at room
temperature, closed at high temperatures. On my '94 Civic it switches at
93°C so you could check it in boiling water. You can also pull the
connector from it and short the two pins of the connector together. Do
this with the ignition on, but the engine not running (and your fingers
far away from the radiator fan!). The radiator fan should turn on. If it
does not, you have a bad fan or a problem elsewhere in the electrical
system. If the fan does turn on when you short those two pins you most
likely have a bad ECT switch (you did say the fan never came on even
with the car overheating?).

As you indicated the car does not overheat while driving, only when
stopped, I would think your thermostat is OK.

 

well if you have a/c a quick way to tell if the fans motors are working is
to simply start the car and turn on the a/c system. Both fans should come
on. At least my 996 accord has two fans if you have one fan then it should
come on while the a/c is on.

That will narrow it down a bit.

 

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

Worss,

With the engine COOL or COLD, open the radiator cap and look inside. It
should be full to the top. If it's not full enough, top it up. The stuff
you added to the reservoir would eventually get sucked into the rad,
after you run (and overheat) the engine a few more times, but only if
the cooling system is intact (which it probably isn't if your coolant is
low).

Without enough coolant, some sensors aren't even emmersed, and the
thermostat won't open no matter how hot it gets in your engine, if it's
not sitting in coolant... (Fans also may not run)

Follow the directions in the owner's manual an check ALL your fluid
levels on a regular basis. Keeps Murphy's Law at bay.

'Curly'
====================

 

Thanks for the input. I started the car, turned on the A/C and checked the
two fans. Neither one is running. Should they come on immediately when I
start the car or will the fans only come on when the temperature sensors
reach a certain temperature?

Thanks,
Bill

 

Sounds like you have a blown fuse or a bad connection somewhere, unless both
fan motors are burned out. Try applying power directly to the fan
connectors and see if the fan run. Fans are run by relays, so
a) check the power to the hot side of the relay. This may be supplied by a
fusible link.
b) if OK, check the relay control circuit. This is where you should find a
fuse. Does anything else not work?


Stewart DIBBS

 

You should take your car immediately to a dealer. They are the only ones who
are experienced enough to be able to deal with this problem.

 

And all the mechanics in other garages, and of course the knowledgeable
people in this NG, are not?

Stewart DIBBS