The "Help! I have no heat!" post - Maintenance and Repair Forum

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The "Help! I have no heat!" post
Tuesday, November 11, 2003 8:24 PM
With winter coming up, I'm guessing this post will start appearing more and more. The following will be a step-by-step diagnostic procedure. If you need instructions on how to perform one of the steps listed below, please consult a repair manual. (Can this be made a sticky? Delete what's in these brackets if it can.)

#1. When you say "I have no heat", please differentiate between "Cold air blows out of my vents" or "There is no air blowing altogether".

#2. If the case is "I have no heat", the cheapest and easiest first step is to replace the thermostat. If the thermostat is stuck in the open position, it will not allow the coolant to reach a hot enough temperature to produce heat. This is also a good time to check condition of the coolant, and flush/refill the system if it is questionable.

#3. If the thermostat has been replaced, check next to make sure your temperature control cable has not come unhooked from the back of the HVAC controls. If this happens, the air vents inside the dash will not shift properly, and one or more settings may be operating at the same time, adversly affecting vent temperature.

#4. If the thermostat is verified to be good, the coolant in good shape, and the HVAC controls operating properly, odds are, the cause is a plugged heater core. In this case, the heater core must be replaced, and it isn't a half bad idea to replace the heater hoses, since you're in the area.

Note: These diagnostic procedures are only valid if the vehicle is NOT overheating. If the vehicle is overheating and there is no heat, there is a different set of problems, and a standard overheating diagnosis should be taken instead. <br>

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Re: The
Thursday, November 13, 2003 11:52 AM
My car already overheated/melted...........
Re: The
Sunday, November 16, 2003 10:45 AM
what if there's no air blowing out at all?

<br>

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Re: The
Monday, November 17, 2003 9:34 AM
Then check your heater Fan

Good tips Zliner. It's always nice when someone simplifies something. <br>


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Re: The
Tuesday, November 18, 2003 12:08 PM
what if the heat only works on the highest setting, same with AC on the lower settings it doesnt blow out any air.
Re: The
Tuesday, November 18, 2003 2:42 PM
Your blower reisitor is burned out. It's located on the fan housing. GM part number is 52476725. Here's a post about it:

<a/ href="http://www.j-body.org/forums/read.php?f=11&i=45927&t=45927">Blower Resistor Post</a>


<br>

Blind Julius

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Re: The
Tuesday, November 18, 2003 2:43 PM
mantas batas wrote:

what if the heat only works on the highest setting, same with AC on the lower settings it doesnt blow out any air.


The infamous blower motor resistor. Search this forum. There are dozens of posts on it. <br>

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Re: The
Wednesday, November 19, 2003 10:50 AM
what if i replaced my heater core and heater core hoses to regular heater hose and antifreeze leaks past the hose on the passenger side hose into the heater core case and drips on the downpipe. Despite the clamp being tight. and why did the old heater hose have that H thing on there, and could the spring inside the heater hose be blocking up the hose? <br>



Re: The
Wednesday, November 19, 2003 3:16 PM
Very good info. I'll keep it in mind this winter when my car is at home, and I'm at school :

Jon: Good to see you have a good since of humor out of a TERRIBLE incident. How's the new project coming?
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Re: The
Sunday, November 23, 2003 4:25 PM
Here's a trick I learned back in Canada..

When it's very, very cold out (less than 32 degrees Fahrenheit, or 0 Celcius), it's helpful to take a piece of cardboard and 'block' a portion of your radiator. This will prevent most of the air from passing through your radiator and will allow the engine to warm up easier (and faster).

You don't have to cover the whole thing, maybe only 1/3-1/2 of it. Another trick is to run the correct mixture of coolant, and to run a higher temperature thermostat over the winter (say, 195 or 210 rather than a 160 or 180).

Later,
Colin <br>

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Re: The
Monday, November 24, 2003 9:27 PM
Very good post, however I would like to interject one more thing if you fall in the "air blows but I have no heat".

Check your coolant level. Yes, I know this sounds redundant, but I've seen it numerous times where the heater would die because the coolant would go down. Not enough to turn on the sensor, but enough to where it wouldn't flow through the heater core. Refilled the coolant, instant heat. <br>


2002 Cav LS Sport. Waiting until I own it, not the bank before I start making major mods. <grin>

Re: The
Wednesday, November 26, 2003 12:09 PM
The Sarge wrote:

Check your coolant level. Yes, I know this sounds redundant, but I've seen it numerous times where the heater would die because the coolant would go down. Not enough to turn on the sensor, but enough to where it wouldn't flow through the heater core. Refilled the coolant, instant heat.


Definitly something I overlooked, and very good advise. I may have "backhandedly" covered this with the note about the properly functioning cooling system, but it never hurts to check fluid levels regardless of problems. <br>

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Re: The
Wednesday, November 26, 2003 7:22 PM
good tips my retarded heater core started leaking its a$$ off need new carpet any suggestions <br>

die honda die
Re: The
Wednesday, November 26, 2003 8:16 PM
So is Dex-cool ethylene glycol or propylene glycol or methylene glycol? <br>


War is an ugly thing, but not the ugliest of things. The decayed and
degraded state of moral and patriotic feeling which thinks that
nothing is worth war is much worse. The person who has nothing for
which he is willing to fight, nothing which is more important than his
own personal safety, is a miserable creature and has no chance of
being free unless made and kept so by the exertions of better men than
himself.
John Stuart Mill

Re: The
Wednesday, November 26, 2003 8:19 PM
Sorry just found out on my own. But how many people know the answer. <br>


War is an ugly thing, but not the ugliest of things. The decayed and
degraded state of moral and patriotic feeling which thinks that
nothing is worth war is much worse. The person who has nothing for
which he is willing to fight, nothing which is more important than his
own personal safety, is a miserable creature and has no chance of
being free unless made and kept so by the exertions of better men than
himself.
John Stuart Mill

Re: The
Thursday, November 27, 2003 6:01 PM
Ethelyne glycol. Most all antifreeze is ethelyne glycol based, meaning the myth about mixing Dex-cool and standard antifreezes is false. <br>

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Fiero - Have you had your brush with death today?
Re: The
Friday, November 28, 2003 10:51 AM
also, if you have hot air blowing, but little air flow, but all the speeds work then check that the fins of the heater core arent plugged up with grime. this is what happened to me and i just cleaned it out with varsol and a toothbrush and it fixed it right up. <br>

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Re: The
Friday, November 28, 2003 10:46 PM
. <br>

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Heres my problem with my heater
Friday, December 05, 2003 4:25 AM
My heater works fine, once it gets going... In the recent cold mornings, i get in the car, let it warm up some, then head on my way. I also turn my heater on to full, and fan on to full. Thing is, the fan don't go. If i put it to defrost, i know I am getting heat because i can see it ever so slowly working on the very lower of the windshield. Now, it isnt untill about after 10-20 minutes of driving, the fan will all of a sudden come on. And my heater is going like nothing was ever wrong. Some suggested the fuse, but if the fuse was gone, then it wouldn't work at all. Is there a relay in there, because maybe the relay gets frozen because os some amount of moisture, and once the motor gets hot enough, it warms the relay up, and away i go. Anywho, any suggestions as to how to fix this please. <br>

Old enough to know better, but young enough to not give a @!#$!
Re: Heres my problem with my heater
Friday, December 12, 2003 2:30 PM
every time I turn my heat on a loud noise comes from under my glove box. is this the blower motor and is it going out?? i takes forever for my heat to HEAT up, this is probably because I have a huge leak somewhere in my anti-freeze lines but could this also be the problem?


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Re: Heres my problem with my heater
Friday, December 12, 2003 6:59 PM
First, do you have a leak or not? If you do, that will have to be addressed first.

Second, the blower motor is in that general vicinity, but more towards the windshield/firewall. <br>

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Re: Heres my problem with my heater
Sunday, December 14, 2003 3:11 PM
Ok here's the problem I'm having, Heater works fine plenty of hot air! The problem is when I try to turn the fan up to anything above the first setting, there is a terrible vibration like something is hitting one of the fan blades, I'd take it to the dealership but I don't want one of those hacks taking apart my beautifully painted dashboard. Can someone tell me how I would go about getting at the blower itself? I've taken apart my dash many times and I don't think I have ever come across it, probably since it is not located near the top because I only take off the parts that need to be painted. Please help this noise sounds terrible and it is probably something simple like a piece of plastic stuck on it or something! Thanks! <br>

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Re: Heres my problem with my heater
Sunday, December 14, 2003 3:54 PM
The blower motor can and should be accessed from under the hood. A repair manual will list the procedure needed to do this. <br>

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Re: Heres my problem with my heater
Monday, December 15, 2003 8:53 PM
what if you change the thermostat, and it the temp stays in normal operating range for about 45 min of mixed stationary and motion, then temp drops (gauged and from the vents) and can't even get to the bottom of the operating range with the entire rad blocked by cardboard, then replace the temostat, and it the temp stays in normal operating range for about 45 min of mixed stationary and motion, then temp drops (gauged and from the vents) but this time warms up somewhat quickly when stationary?

do i just have all the luck when it comes to themostats? <br>

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Re: Heres my problem with my heater
Thursday, December 18, 2003 8:44 AM
Thermostats are a cheaply made, mass produced part. I've seen people buy three bad ones in a row before. My advise, never buy the $1.99 off-brands from AutoZone or wherever. Spend the 5-6 bucks on a Stant Superstat. We've had a much lower failure rate with them. <br>

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