NO HEAT !! please help
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
NO HEAT !! please help
I have no heat. this has been an issue for some time but have never looked into it. I can replace what needs to be replaced but have never looked into what is wrong...How do I check to see what parts need to be replaced or fixed? any tests that can be done. I have some dry rotted rubber lines in my engine compartment that MIGHT have something to do with the problem. I will post pics tomorrow but any info will help !!
Team Owner
Joined: May 1999
Posts: 22,830
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From: Columbus Ohio
CI 3-4, 8-9-10 Veteran
St. Jude Donor '06-'08-'10
Step #1: Make sure the radiator is full. On most cars the heater usually runs empty and and you lose heat if first if the coolant is low.
Step #2: Make sure thermostat is working and engine gets up to temp
Step #3: Check to make sure the heated coolant is flowing to the heater core
Step #4: Make sure you have air flow through the core into the car.
Step #2: Make sure thermostat is working and engine gets up to temp
Step #3: Check to make sure the heated coolant is flowing to the heater core
Step #4: Make sure you have air flow through the core into the car.
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
I just replaced my T-stat. I just refilled my coolant and I have no idea where the heater core is or what it looks like. I guess its under my dash in the passanger side. And my a/c is ice cold during the summer and air comes out so I dont know where to look to see if air is comming out of the heater core. And how do I check to see if I have coolant going to the heater core?
Team Owner
Joined: May 1999
Posts: 22,830
Likes: 13
From: Columbus Ohio
CI 3-4, 8-9-10 Veteran
St. Jude Donor '06-'08-'10
I just replaced my T-stat. I just refilled my coolant and I have no idea where the heater core is or what it looks like. I guess its under my dash in the passanger side. And my a/c is ice cold during the summer and air comes out so I dont know where to look to see if air is comming out of the heater core. And how do I check to see if I have coolant going to the heater core?
You can just grab them by hand. They don't get so hot that they'll burn but you won't want to hang on to them for long...
The heater control works in one of two ways. One stops the flow of hot coolant through the heater core. The other method always has hot coolant in the heater core but uses doors to seal off the heat when not needed in the car.
Not sure what year you have but I think the LT1 uses the second method. In either case if you don't have hot coolant flow through the core you will not get heat in the car.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
The rotten vacuum hoses will have a lot to do with no heat since the heat doors that open are controlled by vacuum.
On early cars, 84-88, the heater valve is spring loaded to open. vacuum turns off the heat and enables A/C.
If you are experiencing no heat, I suggest you perform the afore mentioned steps, and if you still can't get heat, that you purchase a vacuum pump that you work by hand, and go from point A to B to determine where the vacuum leaks might be.
If the vacuum gauge goes to zero fast, it's a leak. trace that hose till the vacuum holds.
On early cars, 84-88, the heater valve is spring loaded to open. vacuum turns off the heat and enables A/C.
If you are experiencing no heat, I suggest you perform the afore mentioned steps, and if you still can't get heat, that you purchase a vacuum pump that you work by hand, and go from point A to B to determine where the vacuum leaks might be.
If the vacuum gauge goes to zero fast, it's a leak. trace that hose till the vacuum holds.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Cars with electronic air have a electric stepper motor that operates the air blend door to give required air temp.The vac only changes the vent positions
Team Owner
Joined: May 1999
Posts: 22,830
Likes: 13
From: Columbus Ohio
CI 3-4, 8-9-10 Veteran
St. Jude Donor '06-'08-'10
The third method I've seen:
On the Model A Ford the heater was a @ 2" tube through the firewall with a flip lid on it. If you wanted heat you flipped the lid up.
On the Model A Ford the heater was a @ 2" tube through the firewall with a flip lid on it. If you wanted heat you flipped the lid up.
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Burning Brakes
Joined: Feb 2009
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From: Richmond Virginia
Instructor
Joined: Jan 2010
Posts: 174
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From: Austin_Palm Bay_Houston Texas_Florida_Texas
Note: Since you are not getting any heat, and if the problem is your blend door, it will be stuck in a fashion to where you will not be able to see the heater core when you look through the opening in evaporator housing opening(ie the blend door will be covering up the heater core so that no air will pass through it).
Last edited by Al Borman; Feb 7, 2010 at 11:44 AM.
Instructor
Joined: Jan 2010
Posts: 174
Likes: 4
From: Austin_Palm Bay_Houston Texas_Florida_Texas
Get the engine up to temperature, make sure the heat is set as high as it goes and check both hoses, inlet and outlet, running to the passenger side of the firewall. If coolant is flowing through the core both will be hot. They'll be about 1 1/4" in diameter.
You can just grab them by hand. They don't get so hot that they'll burn but you won't want to hang on to them for long...
The heater control works in one of two ways. One stops the flow of hot coolant through the heater core. The other method always has hot coolant in the heater core but uses doors to seal off the heat when not needed in the car.
Not sure what year you have but I think the LT1 uses the second method. In either case if you don't have hot coolant flow through the core you will not get heat in the car.
You can just grab them by hand. They don't get so hot that they'll burn but you won't want to hang on to them for long...
The heater control works in one of two ways. One stops the flow of hot coolant through the heater core. The other method always has hot coolant in the heater core but uses doors to seal off the heat when not needed in the car.
Not sure what year you have but I think the LT1 uses the second method. In either case if you don't have hot coolant flow through the core you will not get heat in the car.
Although probably not your problem, here is a pic of the heater flow restrictor. It attemps to regulate the pressure going to the heater core by means of a spring and plunger inside a plastic POS housing. I have had one of these burst on me before(this assembly is glued together, Arghhh). Anway, this is the "Inlet" hose to your heater core.
Last edited by Al Borman; Feb 7, 2010 at 02:50 PM.
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
Likes: 0
From: Strongsville Ohio
you guys are amazing thanks soo much. I am going to see if my lines going into my firewall are hott while operating temps are reached. Then im going to check the flipper door thing. Thanks guys ill b back on in a bit to discuss more..
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
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From: Strongsville Ohio
coolant lines going into my firewall to the heater core were warm but in no way hott. they might have only been warm due to me driving for half hour then checking them. I looked for all dry rotted lines and found 2. they are both going into some round black looking thing RIGHT above the battery. one line feeds into the ASR housing which I took off and am going to replace. The other I disconnected but it leeds back into my car where my feet are under the dash. I have no idea where it really goes. There is no way to really stick me head in there and look at how it comes off or goes back on. I am confused what these lines do and what they both feed into.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
When the core plugs - coolant flows over the top but not through it - temp of the hoses doesn't tell you much of anything; though the fact that yours aren't scalding, would indicate decent flow through the core. Pulling the Blower Module will confirm a Temp Door problem. Probably a stripped gear which is common for this Year.
I've got no idea what hoses you're talking about, but there is a vacuum source through the Firewall to the HVAC programmer. If it's busted it's going to be Defrost only so if the vent position is correct with whatever's dialed into the Panel, that ain't the hose you're concerned with.
I've got no idea what hoses you're talking about, but there is a vacuum source through the Firewall to the HVAC programmer. If it's busted it's going to be Defrost only so if the vent position is correct with whatever's dialed into the Panel, that ain't the hose you're concerned with.
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,151
Likes: 0
From: Strongsville Ohio
I have had no heat for about 2 years but now that I am in the mood to fix stuff I fidgured I would attack the problem. I replaced the thermo stat after it stuck and busted my lines. So yes the heat issue was current before the t-stat problem. I will pull the housing of and see whats going on
P.S I did notice a while ago under my passanger floor mat that there was water. BUT I didn't know till now that its coolant and probably comming from my heater core.
P.S I did notice a while ago under my passanger floor mat that there was water. BUT I didn't know till now that its coolant and probably comming from my heater core.
Instructor
Joined: Jan 2010
Posts: 174
Likes: 4
From: Austin_Palm Bay_Houston Texas_Florida_Texas
I have had no heat for about 2 years but now that I am in the mood to fix stuff I fidgured I would attack the problem. I replaced the thermo stat after it stuck and busted my lines. So yes the heat issue was current before the t-stat problem. I will pull the housing of and see whats going on
P.S I did notice a while ago under my passanger floor mat that there was water. BUT I didn't know till now that its coolant and probably comming from my heater core.
P.S I did notice a while ago under my passanger floor mat that there was water. BUT I didn't know till now that its coolant and probably comming from my heater core.
Do you have electronic AC system in your '94 ????????
