raczyk

It all started when the engine started to overheat @ idle, couple days later it would not start at all. It works now once again, but the overheating problem is still there.

Here is what I checked so far:
1. Tried checking the ECU for error codes, but the engine light just stayed on. With that said I have checked the fuse box under the hood and fuse #32 (PGM_FI ECU, Clock) is burned. Could this be causing the overheating at idle? Also the constant light means the ECU is runing in backup mode, what is that?
2. Jumped the radiator fan and it works fine.

The next thing I will try is to check the thermostat by heating the car and checking the temp. of the top radiator hose.

Did you guys ever experience this, or maybe can point me in the right direction?

BTW: It is a 1993 Honds Civic.

Cheers!

imported_05CivicSi

still on your original rad? maybe the core is shot

crvtecEG

how did you jump the rad? with the thermoswitch (fan switch) in the thermostat housing?
Does the rad fan turn on by itself while the car is sitting still idling?

raczyk

Rad is new, was replaced a year ago.

I still have to check if the fan turns on when ten its heated, thx for suggestion.

The fan was jumped by feeding it direct power from the battery to the fan motor. (was attached right to where the fan / radiator is).

imported_05CivicSi

ok well if the rad is new, it could be an air pocket in the coolant or the Tstat could be seized, usually overheating at idle wouldent be caused by the fan not coming on

raczyk

Hmm i c, n does the ECU have enything to do with controlling the fan?

imported_05CivicSi

ECU is over my head, when my rad went my car didnt overheat at idle so this is a little weird to me

crvtecEG

check when the fan comes on....when your car is not moving. The whole reason for the fan is to pull air through the rad while the car isn't moving.
raczyk:
turn your car on and let it idle for about 10-15 minutes (with the hood closed). Check to see if the fan comes on, it should. If it doesn't, turn the car off and unplug the thermoswitch (fan switch, located in the thermostat housing) and jump it (like you jump the service connector checking the ecu codes). With the fan switch jumped the fan should turn on as soon as you start your car.
Are both the upper and lower rad hoses hot after your car idles for a while?
Also, try burping the coolant system. When the car is cool, take off the rad cap, turn the heat on full and let the car run for a while, adding coolant/water when necessary to keep the rad full. As the car runs with the cap off this will burp the cooling system and let the air bubbles (if there are any) escape.

raczyk

"Are both the upper and lower rad hoses hot after your car idles for a while?"
The upper radiator hose is very hot, while the bottom radiator hose is just hot. I was hoping that the top hose would be cool so i can then just replace the thermostat.

And yes the fan did turn on when the temperature guage went up.

This leaves me with with two more possiblities.

Could it be the coolant sensor (i.e. temperature guage)?
Could it be the head gasket?

crvtecEG you mentioned burping the coolant system, is that the same as bleeding it?

Is there a way to test for a broken head gasket?

crvtecEG

its not the coolant sensor, if it was the fan wouldn't turn on.
About the head gasket, is there oil in your coolant? Is there coolant in your oil (does your oil look like chocolate milk)?
Does your car run crappy and smoke? If your head gasket was blown your car would burn coolant.
A simple compression test can also determine if your head gasket is toast.
Yes, burping the cooling system is the same as bleeding it.

raczyk

I have bleeded the coolant system. While doing so at times bigger bubbles surface, esp when extra throttle was added.
The oil and coolant look fine. Could this mean the head gasket is on its way?

imported_Torrey

lol, this guy hasn't even checked to see if his fan turns on.

Before you do ANYTHING else, make sure your fan turns on.

imported_precision4

I believe that he did!

bdotdan

you need to read the thread again

imported_Torrey

^^^^ Useless comment, instead of helping this guy you're the second person to state the obvious. I read until normal sentances turn into verbal diaherra.

raczyk

Burping the system seemed to work. Drove the car during a hot day and nothing overheated. Thanks to all who provided troubleshooting ideas.

ciao!