Car overheating?

[aces1980]

i have a 91 civic si with a 99 d16y7 and the car tries to overheat. I have checked fuses and everything there is ok. I have power going to the fan realy but i have no power from the relay to the fan connector. Any ideas on what it can be? or any other test that i can do? thanks for you help

[johnb16a2]

You can pull the relay out and test it, you can also wire the fan directly to test it. GL

[bionictony]

my guess is the thermostat. it might be stuck closed so that coolant isnt circulating. just pop the radiator cap and see if coolant is flowing when the car is hot. but be careful cuz some hot coolant will flow out of the top

[aces1980]

Originally Posted by johnb16a2

You can pull the relay out and test it, you can also wire the fan directly to test it. GL

how can i test the fan directly? i have replaced the relay so i know that is not the problem.

[aces1980]

Originally Posted by bionictony

my guess is the thermostat. it might be stuck closed so that coolant isnt circulating. just pop the radiator cap and see if coolant is flowing when the car is hot. but be careful cuz some hot coolant will flow out of the top

i have also replaced the thermostat. and i do see the coolant flowing when the car is hot. Any othere ideas would be greatly apreciated. thanks

[Civic Jim]

maybe the relay was connected up in the incorrect way and you have just replaced it with a new one but still in the incorrect way ????

maybe the fan is broke

[turtlecrxsi]

you can also wire your fan to stay on all the time... mine is and goes right to ignition under dash with a 20a fuse block in between... never overheats

[TheSilentChamber]

Unhook the fan, use use test leads (spare wire, big enough not to melt though) to test it on the battery. If you have air conditioner (weither the compressor is hooked up or not) turn the AC on max and it will override the temp controle and kick the fan on. I have a fan from an 88 I would sell you for like 10 bucks plus shipping if your fan is out.

[crx91]

replace the radiator cap, that might help.I have a friend with a 98 hatchie with the y7.we replaced the thermastat and flushed the system and it turned out to be the cap.funny shit that never made cents.

[Cjz89civic]

Check to see if the coolant line coming from the head into the block on the back side of the motor is kinked. I had this problem about a week after I got the motor in. I turned on the heater just to use it as a by-pass. If its kinked you will get over heating and no fan. Cause the coolant line from the head is what feeds that area of sensors.

ALSO check to see if you have air in the system. To do this start the car, crack open the bleeder screw on the top of the radiator line to the block. If ya get bubbles or air well you guessed it. If it is spirting out then its too hot let it cool add water and do it again. Do this untill you get constant water flow. Also make sure your heater is on cause some times air gets trapped in the heater core and causes a problem the first time you use your heater.

[johnb16a2]

Originally Posted by TheSilentChamber

Unhook the fan, use test leads (spare wire, big enough not to melt though) to test it on the battery. If you have air conditioner (weither the compressor is hooked up or not) turn the AC on max and it will override the temp controle and kick the fan on.

I agree, if the fan runs you probably have a bad wire to the fan or the temp sensor is not working correctly. Also, check the relay anyway, just because it's new doesn't mean it's not defective. Let us know how it turns out. GL

[aces1980]

here is a stupid ? is there any way you can show me a pic of the fan relay, maybe i messed up and changed the one i was not supposed to. I have bled the system many times and i still get the same result. i just found out the fan work cause i used jumper cables to try it. here is another thing i have noticed. when the car runs hot the lower radiator hose is cold and the top one is hot. is this normal? i really apreciate evryones help thanks and keep the suggestions coming guys.

[Cjz89civic]

thats the termostat thats bad CHANGE IT. I know you replaced it but maybe its bad too the only way this will over heat like this is because of flow. There is a block somewhere cause its overheating in the engine and not allowing the water to return to the engine to cool it. Like i said thermostat or maybe a air bubble in the lower part of the engine take the hoses off and run water into them.

[aces1980]

do you think i can get it exchanged at the store i bought it from? i just got it a couple of days ago when i started to have the problem.

[Cjz89civic]

Maybe try. Also try sqweezing the hoses while the radiator cap is off to make sure all the air is out.