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Why wont my car get hot?

PostPosted: Wed Jan 18, 2012 1:37 am
by 93CivicEg
Ok so i know its cold out side but...

My car needle wont get off C if i get in and start it and drive.
So my heat wont be blowing hot.

BUT....

If i start it and let it sit and let it run and heat up then it goes up.

Then when its in the middle i drive it and it stays in the middle.

Same thing happens to my buddys ek

btw my fan doesnt come on since i have the fan switch manually
so it wont because the fans cutting on,

there are no leaks i did a leak down test, and it didnt even budge

i also replace the heater core and Both upper n lower hoses and all heater hoses

PostPosted: Wed Jan 18, 2012 2:06 am
by asianrob
change your thermostat

PostPosted: Wed Jan 18, 2012 4:32 am
by teal_dx
asianrob wrote:change your thermostat


Yep, it could be stuck partially or all the way open.

PostPosted: Wed Jan 18, 2012 4:48 am
by Ajax1989
your your sensor could be bad.. the 1 wire plug under your dizzy.. its a yellow wire

PostPosted: Wed Jan 18, 2012 5:49 am
by 93CivicEg
the coolant temp sensor? i replaced that, if it was bad it wouldnt go up while it is sitting.

i was thinking of the thermostat also, i will replace that soon

PostPosted: Thu Jan 19, 2012 12:00 pm
by 95c1v1c
Thermostat!

PostPosted: Thu Jan 19, 2012 2:56 pm
by Classiccarsrule85
this may be unrelated but my friendd had the same issue with his 4dr eg let it sit and it would heat up drive it and blam it would cool right down turns out it was a bad heater wire in the o2 sensor dont ask me how that works but as soon as i put a new o2 in i didnt do anything else it worked like normal again it was weird but sounds exactly like this problem

PostPosted: Thu Jan 19, 2012 7:00 pm
by 1ACarlos
Sounds like a thermostat to me

PostPosted: Sat Jan 21, 2012 1:33 am
by 93CivicEg
Classiccarsrule85 wrote:this may be unrelated but my friendd had the same issue with his 4dr eg let it sit and it would heat up drive it and blam it would cool right down turns out it was a bad heater wire in the o2 sensor dont ask me how that works but as soon as i put a new o2 in i didnt do anything else it worked like normal again it was weird but sounds exactly like this problem


i just replaced my o2 sensor and it did it before the 02 sensor also

i bought a new thermostat yesterday, will be installing it this week

PostPosted: Sat Jan 21, 2012 3:44 am
by Ajax1989
93CivicEg wrote:the coolant temp sensor? i replaced that, if it was bad it wouldnt go up while it is sitting.

i was thinking of the thermostat also, i will replace that soon


No not the ect but the 1 wire running under your dizzy

PostPosted: Sat Jan 21, 2012 2:20 pm
by bigJOE671
I have the same problem...If you change your thermostat please put up a DIY. I have no idea on how to do it.

PostPosted: Sat Jan 21, 2012 3:03 pm
by Apexracing
bigJOE671 wrote:I have the same problem...If you change your thermostat please put up a DIY. I have no idea on how to do it.



Follow the lower radiator hose as it goes back towards the firewall. Notice it connects to the head just behind the distributer. This is the thermostat housing. Make sure the engine is cold and remove the clamp on the hose. Twisting slightly as you pull remove the hose from the housing(note you will lose some coolant, so place a bucket under your car). Next there are two bolts/screws on the face of the thermostat housing. Remove these and set the cover aside. next pull out your thermostat make note of the direction it was removed and insert the new one in the same manner. making sure the gasket in correctly seated. You might want to purchase a new housing gasket if one is required. reassemble the housing and attach the hose and clamp. Next open up the radiator and add the coolant you lost, use a 50/50 mix or dilute standard antifreeze using the proper amount of water. Add to the radiator until its full leaving the cap off. try to squeeze the lower radiator hose until most of the bubbles come out of the top of the radiator. Then top it off with coolant and start the car, again with the cap off the radiator. turn the heat all the way on, and watch the radiator. as the car begins to heat up and the coolant begins to circulate air bubbles will work there way out the top. Notice the coolant level will drop as air escapes. Keep it topped off every time it drops. when the engine reaches normal operating temp and you have great heat, top off the radiator again and place the cap on. Keep checking the coolant levels over the next few days(always on a cold engine) if the level stays the same then you got all the air out.

Enjoy :)

PostPosted: Sat Jan 21, 2012 3:20 pm
by bigJOE671
Apexracing wrote:
bigJOE671 wrote:I have the same problem...If you change your thermostat please put up a DIY. I have no idea on how to do it.



Follow the lower radiator hose as it goes back towards the firewall. Notice it connects to the head just behind the distributer. This is the thermostat housing. Make sure the engine is cold and remove the clamp on the hose. Twisting slightly as you pull remove the hose from the housing(note you will lose some coolant, so place a bucket under your car). Next there are two bolts/screws on the face of the thermostat housing. Remove these and set the cover aside. next pull out your thermostat make note of the direction it was removed and insert the new one in the same manner. making sure the gasket in correctly seated. You might want to purchase a new housing gasket if one is required. reassemble the housing and attach the hose and clamp. Next open up the radiator and add the coolant you lost, use a 50/50 mix or dilute standard antifreeze using the proper amount of water. Add to the radiator until its full leaving the cap off. try to squeeze the lower radiator hose until most of the bubbles come out of the top of the radiator. Then top it off with coolant and start the car, again with the cap off the radiator. turn the heat all the way on, and watch the radiator. as the car begins to heat up and the coolant begins to circulate air bubbles will work there way out the top. Notice the coolant level will drop as air escapes. Keep it topped off every time it drops. when the engine reaches normal operating temp and you have great heat, top off the radiator again and place the cap on. Keep checking the coolant levels over the next few days(always on a cold engine) if the level stays the same then you got all the air out.

Enjoy :)


Thank YOU!

PostPosted: Sun Jan 29, 2012 2:47 am
by 93CivicEg
well i fixed the thermostat,

come to find out there wasnt even one in there :)

now i got heat, thanks guys

PostPosted: Sun Jan 29, 2012 2:53 am
by Apexracing
93CivicEg wrote:well i fixed the thermostat,

come to find out there wasnt even one in there :)

now i got heat, thanks guys



Awesome!