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Quick question>>are my fans only supposed to come on when my a/c is turned on?

I have a 2004 Honda civic EX manaual>>and I can only seemed to get my fans turned on when my a/c is turned on.

I do have an overheating issue when I go on long drives at a high RPM (if I drive 10 miles at 4,000 RPM and come to a stop it will slightly overheat until I drive again.)

This whole time I have the A/C running, but even with the engine starting to get hot and I turn the A/C off the fans will stop.

Its almost like I have two issues in one, but they could be related.

I have changed.>>>>>

Thermostat
radiator
coolant flush
radiator cap
coolant reservoir
water pump


Any ideas???

 
Rep Power: 518

Needs a head gasket job. Find the sticky thread on overheating.

Your radiator level is going low, causing the overheat, while the reservoir is overfilling or overflowing as fluid is expelled from the radiator..

Fans are supposed to run whenever the compressor is on.
Fans run whenever the temp switch in the stat housing turns them on.

What you are seeing is because the coolant switch location in the cooling system flow does not sense the temp of the coolant leaving the engine.
It senses the temp of liquid coming out of the bottom of the radiator.
There can be plenty of time for the radiator to do its job and negate the need for the fans to run, as determined by the fan switch. Even when everything is working well, any breeze blowing through the radiator can keep it cooled enough to not need the fan for quite a while.

 
Rep Power: 229

if the hoses top and bottom are hot and your fans are not turning on while idling it is your fan, fan switch or fan relay. (my fan switch blew out at 150,000km.

if it cools fine while in motion and overheats while stopped that means that the fans are not turning on to force air through the rad.

you can test this by first taking her for a hard rip then pull over when at operating temperature, if you pop the hood and the fan is not spinning, while ac is off, then there is a fan issue.

To test the fan/fan switch, locate the fan switch, it looks like this

it will be right under your thermostat

-disconnect the electrical socket
-jump the socket with a piece of wire (the plug side not the switch side).
-start the engine.

If the fans spins this means your switch is fried.

If the fan dos not spin either the fan is fried or the relay.

to test that fan just disconnect it from it's electrical socket and connect the battery directly to it, if it does not spin your fan is fried.

if you get to this point and the fan spins, that means that there is no power getting to the fan when it should be. So test the relay. (you can pull the horn relay out and place the fan relay in it's section, if the horn still works then you know the relay is good).

good luck.

 
Rep Power: 0

I forgot to put that in there, I changed the fan switch and ECT sensor

 
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I was able to apply pressure on the system and it held at 16 PSI with no drop-off and no visible leaks.

 
Rep Power: 518

Was the radiator level low? Was the reservoir overfull?



It will probably pass all the usual head gasket checks most people think of while the breach (head gasket leak) is small. It's gotta be a huge failure before it does any of the things most people look for.

Find the sticky on overheating and read about how I prove head gasket failures on this particular engine.

 
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ok thanks. i will check it out. And the reservoir is overfull. The only time it loses coolant is when is purges out the reservoir.

 
Rep Power: 518

Blown head gasket, helllllooooo!

 
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just an updated....prices that I was quoted were out of this world especially for what the car is most likely worth (head gasket replacement)...I used BlueDevil head-gasket sealer and it seemed to work fine "fingers corssed"......though i am most likely going to get a new car...how long does this stuff last for?

 
Rep Power: 518

Until it doesn't?

 
Rep Power: 150

I hear Taps playing...

A unicorn lost its wings today... sad.