Poor Heat-(not a stat)
Thread Starter
Safety Car
Joined: Aug 2006
Posts: 4,147
Likes: 452
From: Port St. Lucie West Florida
Poor Heat-(not a stat)
I have a 95 vert LT1 auto and replaced radiator and thermostat 2 weeks ago.I have the climate control heater/ac.When car is warmed to normal operating temp,I put the heater on 79 dg.I get good heat for 15 minutes and then it gets alot cooler.The heater is blowing cool air.If I shut the car off for a few minutes,and restart car,the heater will be warm for another 15 minutes.If I put the heater on 90 degrees,it stays very hot and will not blow cool air.Any temp below 90 will get cool after awhile.Did replacing the radiator have something to do with this?or was it coincidental.what could cause this.
Thank you
Thank you
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
I'll take a 'SWAG' at it.
My 84 had a similar symptom and it was the heater core.
It was stopping up with 'snarf' so the hot water couldn't make it thru.
Here's what I di to fix it:
1)Removed the hoses from the firewall.
2)Connected about 3 feet of 'test' hose to the two core water connectors.
I thinkone was 5/8" and I don't remember size of the other one.
3)Connected a garden hose to one of the hoses.
Position the other so water wouldn't squirt all over the engine/car.
4)Power flushed the heater core.
5)Reversed the position of the hoses
6)Power flushed again.
A lot of nasty looking stuff came out when I did this.
Mines been ok for two years since then.
There also COULD' be a vacumn problem causing improper operation of the air diverter doors.
My 84 had a similar symptom and it was the heater core.
It was stopping up with 'snarf' so the hot water couldn't make it thru.
Here's what I di to fix it:
1)Removed the hoses from the firewall.
2)Connected about 3 feet of 'test' hose to the two core water connectors.
I thinkone was 5/8" and I don't remember size of the other one.
3)Connected a garden hose to one of the hoses.
Position the other so water wouldn't squirt all over the engine/car.
4)Power flushed the heater core.
5)Reversed the position of the hoses
6)Power flushed again.
A lot of nasty looking stuff came out when I did this.
Mines been ok for two years since then.
There also COULD' be a vacumn problem causing improper operation of the air diverter doors.
Le Mans Master
Joined: Dec 2003
Posts: 5,768
Likes: 33
From: Van Steel Corvettes
St. Jude Donor '12-'13
Nope. It's the tempature actuator. You have the electronic control correct? the heater door isn't opening properly. The gear is stripped out and will have to be replaced...AKA you have to pull out the dash. I'm having to have mine replaced now. Just spend a needless $900 in the A/C programmer cause that's what the first code is...second code is the tempature actuator which was the main cause. It's an $80 part...just the labor is going to be a major PITA.
I'll take a picture of a part you can remove under the hood and you can see the door (just three screws). Most likely it will just slightly move and close, move and close, repeatedly. A long screwdriver can open the door, and when you set the A/C lower it will close it...just won't be able to open it again without the screwdriver. Just saw this technique used today.
I'll take a picture of a part you can remove under the hood and you can see the door (just three screws). Most likely it will just slightly move and close, move and close, repeatedly. A long screwdriver can open the door, and when you set the A/C lower it will close it...just won't be able to open it again without the screwdriver. Just saw this technique used today.
Last edited by shakedown067; Jan 13, 2007 at 12:04 AM.
Thread Starter
Safety Car
Joined: Aug 2006
Posts: 4,147
Likes: 452
From: Port St. Lucie West Florida
Thank you-Ill look into the temperature actuator.I doubt the heater core is clogged because Im getting plenty of heat when set to 90 dg. Did you have the same problem as I did? I do have the electronic control.Can you please post pix for location of door.Thanks again shakedown067
Last edited by enventr; Jan 13, 2007 at 05:25 AM.
Racer
Joined: Jun 2006
Posts: 408
Likes: 0
From: Elkton MD
Cooling heat
It sounds more like the ambient air temperature sensor isn't placed correctly so it's sensing the radiator temp rather than the air temp. I think his sensor is located on the passenger side under the front corner of the radiator on a '95.
Was the ambient air sensor position upset during the radiator replace?
Was the ambient air sensor position upset during the radiator replace?
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Le Mans Master
Joined: Jul 2004
Posts: 5,865
Likes: 6
From: Saraland Alabama
St. Jude Donor '11-'12-'13-'14-'15-'16
I am only a shadetree mechanic but I agree that since the heater does produce heat for awhile that it is not the heater core stopped up.
I also agree that it is likely something to do with the ambient temp sensor located under the radiator since the radiator was R & R by a shop that may not not have even known what the sensor was for and how it should be located.
The fact that the heat still cycles if set at 90 degrees or above rules out, in my mind, the possibilty of the gears being stripped out on the air doors. If that were the case you would have to take the long screwdriver to it to reset it each time and that is not the case.
I no longer have my factory C-4 manuals as I sold them when I sold my C-4 but if you have a manual it might show the positioning of the ambient temperature sensor on the radiator. If you don't have the manual and no one on here can provide that info I would recommend that you look at the sensor on a car just like yours and check out the positioning.
Good luck in solving this problem. I definitely think the problem is under the hood rather than the dash!
I also agree that it is likely something to do with the ambient temp sensor located under the radiator since the radiator was R & R by a shop that may not not have even known what the sensor was for and how it should be located.
The fact that the heat still cycles if set at 90 degrees or above rules out, in my mind, the possibilty of the gears being stripped out on the air doors. If that were the case you would have to take the long screwdriver to it to reset it each time and that is not the case.
I no longer have my factory C-4 manuals as I sold them when I sold my C-4 but if you have a manual it might show the positioning of the ambient temperature sensor on the radiator. If you don't have the manual and no one on here can provide that info I would recommend that you look at the sensor on a car just like yours and check out the positioning.
Good luck in solving this problem. I definitely think the problem is under the hood rather than the dash!
Le Mans Master
Joined: Dec 2003
Posts: 5,768
Likes: 33
From: Van Steel Corvettes
St. Jude Donor '12-'13
The fact that the heat still cycles if set at 90 degrees or above rules out, in my mind, the possibilty of the gears being stripped out on the air doors. If that were the case you would have to take the long screwdriver to it to reset it each time and that is not the case.
I'll still take some pics since it's a quick and easy to check.