Heater problems

foxbodystang · December 27th, 2006, 12:43 AM

I have an 86 GT that I just recently purchased, when I bought it didnt have any of the heater hoses because the recent owner bypassed the heater, but still left the heater coil and everything else intact, I just bought some heater lines and hooked it up the way it should go but I am not getting any hot air, the blower works but only through the defroster area. I was thinking it could be the controls but I am not certain. Please HELP!! If you know an answer!!

foxbodystang · December 27th, 2006, 12:45 AM

If anyone knows please let me know!!!

NYHigH · December 27th, 2006, 01:14 AM

Hey, assuming that the heater hoses are hooked up correctly, i can't see why it wouldn't be blowing hot air except that maybe either you don't have the hot/cold knob turned to hot. If you do, pull off the hot/cold knob and look at the back of it and make sure the key-way is not split. If it is, it might not be turning the key(or whatever that little metal thing the knob is supposed to turn). I had the same problem with mine.

Other than that, let me know why you are only blowing air out of the defroster because mine does the same thing and i don't know what to do? HAHA

Stangzilla · December 27th, 2006, 01:22 AM

you prob have a vacuum line under the dash not connected or something...The vents are controlled by vacuum and I think it defaults to the defroster if you lose vacuum. as far as it only blowing cold air the temp knob is prob not working. Assuming you have one heater hose connected to the bottom fitting on the water pump and the other going to the back of the intake manifold. ya never know you could have a plugged heater core maybe something made a home in there...I've seem weirder things in my 34 years...

NYHigH · December 27th, 2006, 01:34 AM

Hey Stangzilla, that my mustang has the same problem with the blower going to the defroster. My idle has been very high and i could not figure out what is wrong....Could that vacum hose for the blower have anything to do with it....................Stangzilla, or anyone if you will help thanks

Stangzilla · December 27th, 2006, 01:37 AM

that i dont know sorry but i am sure someone will.. hold tight

83 5.0 · December 29th, 2006, 10:35 PM

Feel the heater hoses after warm up, are they warm from coolant running through them? Probably a clogged core.

The vacuum feed is usually from the splitter/vacuum manifold on the firewall, try and pinch (or block) the hoses one by one to see if your idle goes down. This should be the one that was leaking.

The vacuum canister under the dash could be leaking, pull the vacuum hose off it and block the hose to see if the idle changes.

This is a PITA but sometimes the only way to find vacuum leaks.

Good Luck

NYHigH · December 30th, 2006, 10:34 PM

Is the vacum canister that stock fuel filter looking thing behind the glove compartment?

83 5.0 · January 1st, 2007, 09:42 PM

Yes it is. It should have a lever attached to it, and a vacuum hose on the back side.

It has a diaphragm in it which can leak. I forgot to mention that there is a vacuum reservoir also, I think it is usually inside the passenger fender, if some one could correct me if I am wrong.

83 5.0 · January 1st, 2007, 10:59 PM

Found this vacuum guide, hope it helps

NYHigH · January 2nd, 2007, 01:49 AM

Wow, that's a nice picture thanks. I'm gonna see what i can do. I'm not near the car right now but that vacuum canister from what i remember last time, has a vacuum hose coming out the top. I don't remember a lever but i'll check again. I also did pull the hose off of the canister while the car was running and while i was messing with the controls, and i did not get any vacuum out of it. I also did not mention that i've done an engine swap and switched to carb.

83 5.0 · January 2nd, 2007, 10:20 AM

Carb or efi won't make a difference if the vacuum is okay, my 83 convertible is carbed (93 motor which was efi) and I don't have any problems with the defrost etc.

Good Luck

NYHigH · January 2nd, 2007, 09:13 PM

Well what i actually meant was, maybe it was something i disconnected in the process of the swap......i have to really check again, but in the passanger side rear corner of the engine compartment, there are tiny vacuum lines for where the a/c equipment used to be, and no vacuum is coming out of those some i'm thinking the main vacuum line to the whole heater/a/c control is disconnected or something.........i appreciate the help.

83 5.0 · January 2nd, 2007, 11:37 PM

Might want to start where the vacuum splits on the firewall and work your way intothe interior to see where you lose the vacuum. Maybe it's the check valve?

NYHigH · January 2nd, 2007, 11:59 PM

good point......off too ripping the whole dash out tomorro haha........thankyou

December 27th, 2006, 12:43 AM	#1
foxbodystang Newbie Join Date: Dec 2006 Posts: 3	Heater problems I have an 86 GT that I just recently purchased, when I bought it didnt have any of the heater hoses because the recent owner bypassed the heater, but still left the heater coil and everything else intact, I just bought some heater lines and hooked it up the way it should go but I am not getting any hot air, the blower works but only through the defroster area. I was thinking it could be the controls but I am not certain. Please HELP!! If you know an answer!!

December 27th, 2006, 01:14 AM	#3
NYHigH Regular Join Date: Dec 2006 Posts: 170	RE Hey, assuming that the heater hoses are hooked up correctly, i can't see why it wouldn't be blowing hot air except that maybe either you don't have the hot/cold knob turned to hot. If you do, pull off the hot/cold knob and look at the back of it and make sure the key-way is not split. If it is, it might not be turning the key(or whatever that little metal thing the knob is supposed to turn). I had the same problem with mine. Other than that, let me know why you are only blowing air out of the defroster because mine does the same thing and i don't know what to do? HAHA

December 27th, 2006, 01:22 AM	#4
Stangzilla MM Fanatic Join Date: Aug 2006 Location: On my way to Baines's house!! Posts: 3,267	you prob have a vacuum line under the dash not connected or something...The vents are controlled by vacuum and I think it defaults to the defroster if you lose vacuum. as far as it only blowing cold air the temp knob is prob not working. Assuming you have one heater hose connected to the bottom fitting on the water pump and the other going to the back of the intake manifold. ya never know you could have a plugged heater core maybe something made a home in there...I've seem weirder things in my 34 years... __________________ Rotating The Earth 1320 Feet At A Time!! Today, I found out that when I masturbate at night while watching internet porn I cast a huge shadow on the curtain and the entire street is able to see it.

December 27th, 2006, 01:37 AM	#6
Stangzilla MM Fanatic Join Date: Aug 2006 Location: On my way to Baines's house!! Posts: 3,267	that i dont know sorry but i am sure someone will.. hold tight __________________ Rotating The Earth 1320 Feet At A Time!! Today, I found out that when I masturbate at night while watching internet porn I cast a huge shadow on the curtain and the entire street is able to see it.

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December 27th, 2006, 12:45 AM	#2
foxbodystang Newbie Join Date: Dec 2006 Posts: 3	If anyone knows please let me know!!!

December 27th, 2006, 01:34 AM	#5
NYHigH Regular Join Date: Dec 2006 Posts: 170	Hey Stangzilla, that my mustang has the same problem with the blower going to the defroster. My idle has been very high and i could not figure out what is wrong....Could that vacum hose for the blower have anything to do with it....................Stangzilla, or anyone if you will help thanks

December 29th, 2006, 10:35 PM	#7
83 5.0 Regular Join Date: Aug 2006 Location: Toronto Ont. Canada Posts: 255	Feel the heater hoses after warm up, are they warm from coolant running through them? Probably a clogged core. The vacuum feed is usually from the splitter/vacuum manifold on the firewall, try and pinch (or block) the hoses one by one to see if your idle goes down. This should be the one that was leaking. The vacuum canister under the dash could be leaking, pull the vacuum hose off it and block the hose to see if the idle changes. This is a PITA but sometimes the only way to find vacuum leaks. Good Luck

December 30th, 2006, 10:34 PM	#8
NYHigH Regular Join Date: Dec 2006 Posts: 170	Is the vacum canister that stock fuel filter looking thing behind the glove compartment?

January 1st, 2007, 09:42 PM	#9
83 5.0 Regular Join Date: Aug 2006 Location: Toronto Ont. Canada Posts: 255	Yes it is. It should have a lever attached to it, and a vacuum hose on the back side. It has a diaphragm in it which can leak. I forgot to mention that there is a vacuum reservoir also, I think it is usually inside the passenger fender, if some one could correct me if I am wrong.

January 2nd, 2007, 01:49 AM	#11
NYHigH Regular Join Date: Dec 2006 Posts: 170	Wow, that's a nice picture thanks. I'm gonna see what i can do. I'm not near the car right now but that vacuum canister from what i remember last time, has a vacuum hose coming out the top. I don't remember a lever but i'll check again. I also did pull the hose off of the canister while the car was running and while i was messing with the controls, and i did not get any vacuum out of it. I also did not mention that i've done an engine swap and switched to carb.

January 2nd, 2007, 10:20 AM	#12
83 5.0 Regular Join Date: Aug 2006 Location: Toronto Ont. Canada Posts: 255	Carb or efi won't make a difference if the vacuum is okay, my 83 convertible is carbed (93 motor which was efi) and I don't have any problems with the defrost etc. Good Luck

January 2nd, 2007, 09:13 PM	#13
NYHigH Regular Join Date: Dec 2006 Posts: 170	Well what i actually meant was, maybe it was something i disconnected in the process of the swap......i have to really check again, but in the passanger side rear corner of the engine compartment, there are tiny vacuum lines for where the a/c equipment used to be, and no vacuum is coming out of those some i'm thinking the main vacuum line to the whole heater/a/c control is disconnected or something.........i appreciate the help.

January 2nd, 2007, 11:37 PM	#14
83 5.0 Regular Join Date: Aug 2006 Location: Toronto Ont. Canada Posts: 255	Might want to start where the vacuum splits on the firewall and work your way intothe interior to see where you lose the vacuum. Maybe it's the check valve?

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January 2nd, 2007, 11:59 PM	#15
NYHigH Regular Join Date: Dec 2006 Posts: 170	good point......off too ripping the whole dash out tomorro haha........thankyou

Heater problems

Heater problems

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