I will tear this car apart piece by piece if I have to! (long)
12-11-2009, 03:08 PM
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I will tear this car apart piece by piece if I have to! (long)
Car is a 1987 5KCSTQ
First let me apologize to those who have had to endure my posts about this numerous times. We have new peeps on here so hopefully someone will have an idea.
I'll try to keep this as short as possible.
When I first bought the car the heater worked great then it needed a new heater core. I put one in with no problems except ever since I did the job the heat hasn't been the same.
It works fine till it gets in the teens outside then it clearly does not put out the warm temps that its supposed to. Cabin temp will get to 68 or so tops and that is after a while.
I changed the thermostat thinking that the car was running cold even though the temp guage read fine. New thermostat did nothing.
Then a few months ago I took the heater box out again and checked everything. Temp flaps etc. All is well. I even installed a new temp control cable (bowden) and re-calibrated it per Bentley. That has done nothing.
Hoses going to and from the heater core are so hot it's hard to hold them for more than a few seconds. Heater control valve is working. Cooling system has no leaks and I've never had cooling problems with this car. Climate control diagnostic shows everything is working as it should.
For sake of arguement let's say that when the Audi is fully up to operating temp and you turn the heat up all the way to "HI" that car should be blowing 90 degree or warmer air from the floor vent. The car will get uncomfortably warm if left in the "HI" position. Mine used to do this but not anymore. I bet it blows maybe 68-70 degrees tops. This is a problem because when you are trying to initially heat the cabin you need that really hot air to bring the temp up then it backs off and maintains it. What is happening now is I'm trying to heat up a cold car with a max vent temp of 68-70 degrees. This is ridiculous!
For example. I leave the car outside all day and it's zero degrees out. I go to start car and the heat doesn't kick in till the engine starts to warm up (which its supposed to do due to the blower delay) I tend to keep the car set at 68 inside. After the car has been running for even 30 minutes the interior is still not at 68 but the fan is running at high speed. It is warmer but not nearly what is should be.
In the past before I had this problem I'd start the car and as the engine warms up the heat would kick in and you'd feel really hot air coming from the floor then as the cabin reached it's set temp the temp and fan would back off and it would maintain the set temp with ease. I'd have a 68 degree car within 15 mins or less on a day with temps below zero. If I wanted the car at 80 or more degrees it would do that without a problem too.
The other day as I was sitting in traffic and the radiator fan was cycling on and off to test it again I turned it up to "hi" and the air coming out the floor vent was maybe 68-70. Outside temp was about 15 degrees. There is not a one of you on this forum that would sit in my car on a zero degree day and tell me the heat is working properly. You'd all agree that something is up.
I have no air flow problems. All air blows where it should. The A/C works fine. Recir door works as it should. It appears I have a perfect system that just doesn't blow the warm air it should. What am I missing here? Is my engine fan coming on too soon? My temp guage reads the same as the one on SJM's site so I can only assume I don't have an engine temp issue. Also the radiator fan comes on when idling and those supply and return hoses are very hot to the touch. These items do not indicate a cold engine.
It's worth noting that when I did the heater core job I installed everything back like Audi had it. No short cuts. I'm extremely methodical when I work on the car and great care was taken to do the job properly. Everything down to the wire ties was ordered from Audi and replaced as needed. (I'm that picky)I took digital photos, made notes etc so no worries about a hack job.
And to make it even worse my GF says "oh it's an old car what do you expect" Grrrr!!!
Thanks in advance for any replies.
R
First let me apologize to those who have had to endure my posts about this numerous times. We have new peeps on here so hopefully someone will have an idea.
I'll try to keep this as short as possible.
When I first bought the car the heater worked great then it needed a new heater core. I put one in with no problems except ever since I did the job the heat hasn't been the same.
It works fine till it gets in the teens outside then it clearly does not put out the warm temps that its supposed to. Cabin temp will get to 68 or so tops and that is after a while.
I changed the thermostat thinking that the car was running cold even though the temp guage read fine. New thermostat did nothing.
Then a few months ago I took the heater box out again and checked everything. Temp flaps etc. All is well. I even installed a new temp control cable (bowden) and re-calibrated it per Bentley. That has done nothing.
Hoses going to and from the heater core are so hot it's hard to hold them for more than a few seconds. Heater control valve is working. Cooling system has no leaks and I've never had cooling problems with this car. Climate control diagnostic shows everything is working as it should.
For sake of arguement let's say that when the Audi is fully up to operating temp and you turn the heat up all the way to "HI" that car should be blowing 90 degree or warmer air from the floor vent. The car will get uncomfortably warm if left in the "HI" position. Mine used to do this but not anymore. I bet it blows maybe 68-70 degrees tops. This is a problem because when you are trying to initially heat the cabin you need that really hot air to bring the temp up then it backs off and maintains it. What is happening now is I'm trying to heat up a cold car with a max vent temp of 68-70 degrees. This is ridiculous!
For example. I leave the car outside all day and it's zero degrees out. I go to start car and the heat doesn't kick in till the engine starts to warm up (which its supposed to do due to the blower delay) I tend to keep the car set at 68 inside. After the car has been running for even 30 minutes the interior is still not at 68 but the fan is running at high speed. It is warmer but not nearly what is should be.
In the past before I had this problem I'd start the car and as the engine warms up the heat would kick in and you'd feel really hot air coming from the floor then as the cabin reached it's set temp the temp and fan would back off and it would maintain the set temp with ease. I'd have a 68 degree car within 15 mins or less on a day with temps below zero. If I wanted the car at 80 or more degrees it would do that without a problem too.
The other day as I was sitting in traffic and the radiator fan was cycling on and off to test it again I turned it up to "hi" and the air coming out the floor vent was maybe 68-70. Outside temp was about 15 degrees. There is not a one of you on this forum that would sit in my car on a zero degree day and tell me the heat is working properly. You'd all agree that something is up.
I have no air flow problems. All air blows where it should. The A/C works fine. Recir door works as it should. It appears I have a perfect system that just doesn't blow the warm air it should. What am I missing here? Is my engine fan coming on too soon? My temp guage reads the same as the one on SJM's site so I can only assume I don't have an engine temp issue. Also the radiator fan comes on when idling and those supply and return hoses are very hot to the touch. These items do not indicate a cold engine.
It's worth noting that when I did the heater core job I installed everything back like Audi had it. No short cuts. I'm extremely methodical when I work on the car and great care was taken to do the job properly. Everything down to the wire ties was ordered from Audi and replaced as needed. (I'm that picky)I took digital photos, made notes etc so no worries about a hack job.
And to make it even worse my GF says "oh it's an old car what do you expect" Grrrr!!!
Thanks in advance for any replies.
R
12-11-2009, 11:06 PM
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What about the hoses to and from the heater core?
How are the temps on those? Maybe you addressed that and I missed it, but my guess would be air in the system. I'm not trying to assume you would overlook this, but did you run it with the heat on high and cap off of the reservoir? I recently flushed the coolant in my car (PO had nasty neon green stuff in there, replaced with Pentosin blue) and my heat has definitely improved with the flush and bleed off of air.
I still have a small problem with highway speeds, and I think the thermostat is to blame. Heats up alright at a standstill and the gauge sits at about halfway. Highway speeds it will see approximately 1/4, maybe less if it's really cold.
I still have a small problem with highway speeds, and I think the thermostat is to blame. Heats up alright at a standstill and the gauge sits at about halfway. Highway speeds it will see approximately 1/4, maybe less if it's really cold.
12-12-2009, 08:59 AM
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How are the temps on those? Maybe you addressed that and I missed it, but my guess would be air in the system. I'm not trying to assume you would overlook this, but did you run it with the heat on high and cap off of the reservoir? I recently flushed the coolant in my car (PO had nasty neon green stuff in there, replaced with Pentosin blue) and my heat has definitely improved with the flush and bleed off of air.
I still have a small problem with highway speeds, and I think the thermostat is to blame. Heats up alright at a standstill and the gauge sits at about halfway. Highway speeds it will see approximately 1/4, maybe less if it's really cold.
I still have a small problem with highway speeds, and I think the thermostat is to blame. Heats up alright at a standstill and the gauge sits at about halfway. Highway speeds it will see approximately 1/4, maybe less if it's really cold.
R
12-14-2009, 05:31 AM
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Sounds like your vacuum lines are mixed up on the valves behind the center dash on the heater box. If I remember corectly its b-y-g blue-yellow-green(left to right). Also could be the vacuum control unit, under dash right of glove box, there is a procedure to check this, should be in your Bently book, the boden cable is attached to this. When you say the heater control valve is working, you mean it is openning fully? Are the two hoses coming from the heater core both hot when this valve is open? Is there flow?
12-14-2009, 12:38 PM
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Who made the heater core? Did you check with the old one as to how many tubes it has? I had asimilar problem with a replacement radiator that had several fewer tubes in the raduiator to save costs in manufacturing. In warm weather the fan would run almost continously. I finally replaced with a VALEO unit that had the same number tubes running across as the original unit. Now the fan only comes on when idling at a stop, as before. Maybe your unit
12-15-2009, 02:49 AM
#7
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I was never a fan of the Audi climate control center myself. My last 5k had no heat while driving (at temp gauge or in cabin). Heater hoses were hot like yours. I later discovered that the fresh air damper (behind glovebox) was opening while I was driving. Check to make sure that the spring hasn't broken or slipped off. Also check the vacuum circuit at the damper valve. As I understand the system this guy is almost always open to some degree. Set heat to hi, leave fan in auto and just make sure the damper is as close to closed as it can be. Also be sure that your interior temp sensor is operating. If not the fan will blow all day thinking it's not warm yet, which in your case it is not. Try removing the glove box to access the climate control unit and watch the motor that pulls the heater valve cable, or better yet just remove the cable and see if you get heat. (I forget if you pull or push it for heat, I think pull)
My newest to me 5kq had a dozen CC problems so after my hair caught on fire with anger I modified the control unit to meet my needs. I de-soldered one of the vacuum valves from the board, soldered it to a mini-board (from radio shack) and remounted it inside the box. I connected the floor and center vent vac. tubes and ran them thru the mod. valve. Since the defroster is the default it runs in def. like it should. I then mounted a switch on the dash that allows an equal 30% the those three selections which gives me the control I wanted, floor heat is increased by closing vents . I also eliminated the fresh air damper from the circuit. If I want cold/fresh air I know how to open the window, or sunroof for as long as it still works, lol.
I will post a few pics on my page if you want to take a look. It was a lot easier than I made it sound here.
My newest to me 5kq had a dozen CC problems so after my hair caught on fire with anger I modified the control unit to meet my needs. I de-soldered one of the vacuum valves from the board, soldered it to a mini-board (from radio shack) and remounted it inside the box. I connected the floor and center vent vac. tubes and ran them thru the mod. valve. Since the defroster is the default it runs in def. like it should. I then mounted a switch on the dash that allows an equal 30% the those three selections which gives me the control I wanted, floor heat is increased by closing vents . I also eliminated the fresh air damper from the circuit. If I want cold/fresh air I know how to open the window, or sunroof for as long as it still works, lol.
I will post a few pics on my page if you want to take a look. It was a lot easier than I made it sound here.
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12-15-2009, 07:49 AM
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Who made the heater core? Did you check with the old one as to how many tubes it has? I had asimilar problem with a replacement radiator that had several fewer tubes in the raduiator to save costs in manufacturing. In warm weather the fan would run almost continously. I finally replaced with a VALEO unit that had the same number tubes running across as the original unit. Now the fan only comes on when idling at a stop, as before. Maybe your unit
R
12-15-2009, 07:57 AM
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I was never a fan of the Audi climate control center myself. My last 5k had no heat while driving (at temp gauge or in cabin). Heater hoses were hot like yours. I later discovered that the fresh air damper (behind glovebox) was opening while I was driving. Check to make sure that the spring hasn't broken or slipped off. Also check the vacuum circuit at the damper valve. As I understand the system this guy is almost always open to some degree. Set heat to hi, leave fan in auto and just make sure the damper is as close to closed as it can be. Also be sure that your interior temp sensor is operating. If not the fan will blow all day thinking it's not warm yet, which in your case it is not. Try removing the glove box to access the climate control unit and watch the motor that pulls the heater valve cable, or better yet just remove the cable and see if you get heat. (I forget if you pull or push it for heat, I think pull)
My newest to me 5kq had a dozen CC problems so after my hair caught on fire with anger I modified the control unit to meet my needs. I de-soldered one of the vacuum valves from the board, soldered it to a mini-board (from radio shack) and remounted it inside the box. I connected the floor and center vent vac. tubes and ran them thru the mod. valve. Since the defroster is the default it runs in def. like it should. I then mounted a switch on the dash that allows an equal 30% the those three selections which gives me the control I wanted, floor heat is increased by closing vents . I also eliminated the fresh air damper from the circuit. If I want cold/fresh air I know how to open the window, or sunroof for as long as it still works, lol.
I will post a few pics on my page if you want to take a look. It was a lot easier than I made it sound here.
My newest to me 5kq had a dozen CC problems so after my hair caught on fire with anger I modified the control unit to meet my needs. I de-soldered one of the vacuum valves from the board, soldered it to a mini-board (from radio shack) and remounted it inside the box. I connected the floor and center vent vac. tubes and ran them thru the mod. valve. Since the defroster is the default it runs in def. like it should. I then mounted a switch on the dash that allows an equal 30% the those three selections which gives me the control I wanted, floor heat is increased by closing vents . I also eliminated the fresh air damper from the circuit. If I want cold/fresh air I know how to open the window, or sunroof for as long as it still works, lol.
I will post a few pics on my page if you want to take a look. It was a lot easier than I made it sound here.
12-15-2009, 03:11 PM
#10
AudiWorld Member
Randolph...It would be nice if it gave you more control when desired like the newer cars (like hot air out of the dash for example
That was my biggest complaint as well as all of the problems I was having.
If I want warm feet I should be able to just send the hottest dam air right too them,lol!
That was my biggest complaint as well as all of the problems I was having.
If I want warm feet I should be able to just send the hottest dam air right too them,lol!