overheating 94 honda civic

Car overheats when driving, but when at a red light or at idle the car temp
drops. Thermostat works and so does the waterpump. replaced coolant temp
sensor, but the problem is still happening

 

Have you changed coolant lately? Try bleeding the cooling system it
does strange things if there is air in the system.
ernie

 

Also, is the thermostat OEM? If not, replace it.

How many miles and years on the thermostat? If over ten years or 100k miles,
replace.

 

Are your fan(s) coming on?

 

Sure sound like poor circulation due to a plugged rad. Pull the cap off
with the engine cold. Peek inside. What do the tubes look like?

 

how do you know the thermostat works? how did you test it?

 

| >> Thermostat works
He already checked thermostat*, you twit

| thermostat OEM? If not, replace it.
Why must * be OEM ? You just want to sell OEM parts.

| If over ten years or 100k miles, replace.
My F20A's * was made in 1990, & is still fine. * is not known to often fail
www.d-a-p.com/askus.htm. For the same amount of time to replace *, user
can chk either * by dipping * in hot water & see if it opens / connects
current ( to activate the relay which controls fan motor ).
http://hostingprod.com/@aa1car.com/library/overheat.htm

 

non-OEM may have different temperature set points. This part doesn't cost
much. A little more for OEM, and hence certainty in the temperature
setpoints, is a good investment.

Performance degrades with time.

 

| OEM, and hence certainty in the temperature
| setpoints, is a good investment.
My OEM Toyo radiator ( model # 60300 AF ) 's cap puts too little
pressure on coolant : when hot, coolant's air bubbles appear / expand,
so ~1½ cc of coolant always got pushed out of cap & into overflow-
bottle. If I buy a new cap, I'll avoid OEM / Toyo.
I put a o-ring onto cap's bottom seat for cap's gasket to press onto, to
increase cap's spring's pressure on coolant, www.barsleaks.net/faq.html
then cylinder head's water's maximum temperature is lower, because
air bubbles are now smaller so heat can be transferred out fstr : now
tmprtre does not ( used to ) reach the top left corner of my '90 accord
( tmprtre gauge lacks calibration ) 's gear position indicator's D3 box,
in 29°C ambient air. Before I got this new low max tmprtre, I sought
an aluminium radiator to replace my OEM radiator.

| Performance degrades with time.
Bullshit, a thermostat* can work like new unless damaged by over
heating, this is why no car maker's service schedule includes changing
*. In 6-05 I tested my 15yr old * by dipping it in hot water, it opened
fine ( start @ 78°C, fully by 90°C, as specified by honda ).
U just want to push & sell OEM parts.

 

TE Cheah wrote:

dude, that's not correct. thermostats rely on springs, seals and a wax
plug. they all degrade with time and usage.

some manufacturers don't specify transmission oil changes either - does
that somehow mean that the transmission won't benefit from being changed?

i may not care for all of elle's comments, but regarding oem parts for a
honda, she's on the money. if you're a ford or chevy man, sure,
after-market is just as good if not better than the junk oem those
manufacturers use. but honda? honda spec parts are invariably much
superior quality. especially for things like thermostats.

 

Well, could be head gasket. Blown Head gasket's cause oveheating, it's also
likely the radiator needs to be replaced. It's 12 years old after all.
Radiator efficiency degrades with time. Might want to feel the radiator and
see if the heat is evenly distibuted. What happens is the cores near the
center of the radiator cake up so, the center of the radiator is cold and
the out edges are hot. If you feel that, then you need a radiator.

Does the temp go down when you run the heat full blast? If so then it's
another sign the radiator's shot.

I'm in the OEM school myself. other then performance parts I ONLY use OEM
honda parts.

 

I could say the same about you: You work for Autozone and want to push
aftermarket parts.

Fact is the difference in price is not large. To replace an old thermostat
after 150k (which will likely then be the last time it ever needs
replacement) miles is a perfectly good suggestion.

Apprentices repair. Engineers and experienced technicians replace. Because
that's a lot less hassle for just a little more money.

 

It doesn't matter if the heats on or not. When I'm at a stop the het will
drop fast (real fast). I took it to a shop to get tested and they said its
a radiator cooling fan switch. Now I just got to find the switch under the
hood. When I touch the back of the radiator it cool to the touch.

 

Well the fans weren't working, but I changed the coolant tempature sensor
and now one cut on at idle. this might be a dumb question do the fans cut
on whil the car is driveing down the road

 

The fans are controlled by the temperature sensor/relay. If the
coolant temperature hits a certain high set point the fans come on.

Take the connector off the fans and apply voltage directly from your
batter to the fan side connector. Do the fans turn? If so the
problem is your temp sensor relay. If they do not the brushes are
worn out on the fans. Unfortunately, I have not been able to find any
replacement brushes, they are not actually designed to be replaced so
you have to replace the fan motor for the Rad fan and the whole fan
assembly for the AC fan.

Your problem sound like more than that because usually in the winter
at normal operating speeds the temperature would not go up and cause
the fans to come on. Unless you live in the tropics.

 

There telling me (mechanics) Rad.-cooling fan switch. I bought the part but
don't know were the hell it is

 

Normally it's on the gooseneck where the thermostat sits.

 

Rads are just about the only aftermarket parts I'll buy, besides
windshields. There are plenty of decent aftermarket rads for a third dealer
price.

Any other parts, I buy OEM as well.

 

Cheah is a little (well, maybe a lot) whacko. He once claimed that
Hondas had a design defect in that they have an electric clock which
draws electricity from the battery. Also, the design of the Honda
ignition system makes it impossible for the engine to run faster than
3800rpm.

 

You just reminded me that I need to find a decent aluminum radiator. Any
suggestions? The civic overheats when I'm full throttle for extended
periods. I was doing about 110 on the main straight at summit point, looked
down for a sec and the needle had climbed to about 2/3rds it's range.
Turning the heater on brought the temp back down but, I need that rad
before I go back.