Flushed Heater Core, still no heat, suggestions?

[tbmaciii]

I flushed the heater core, about 3 gallons of water in the inlet and some brown/orange crap came out of the outlet, ran it until it went clear. Could it be a bad thermostat?

PS, anyone trying to remove the hoses going into the firewall for the flush, that was a pain in the asssssssssssss

[quattro16]

Sounds like the heater core is clogged with rust and coolant goo. Sorry to say but you will need to change the heater core and flush the system good.

[AvantJunkie]

You may still have an airlock. Did you bleed the system?

[vintagespin]

Oh my god. Please stop making new threads and just use one thread to chronicle your heat problems. This is what I posted in your last thread, to which you never replied:


If you keep refilling it with water, your system isn't going to be cooling nearly as well as it should be. How long have you been refilling it with water? A year, I think you said in the other thread? That's way too much water and way too little G12. Have you been using distilled water, at least?

I don't know how you got on the track that your heater core needs to be replaced or flushed, you haven't given nearly enough information in any of the 4 threads you have started for a consistent or coherent diagnosis from the AZ members.

1. Does your coolant temperature gauge work?
2. Does it rise and stay put at 1/2 way (completely vertical) like it should when working properly?
3. Do you have overheating problems?
4. Have you looked around the engine bay from the top, with a flashlight and with all the covers removed, immediately after driving to look for leaks?
5. Have you looked around the engine bay, from the bottom, with a flashlight and with the bellypan removed, immediately after driving to look for leaks?
6. Have you gone to an Autozone or met up with anybody who has VAG-COM to get scanned for codes?

The only things you have told us are that:
-You have no heat
-You tried bleeding air from the system (what procedure did you follow?)
-You tried playing with the thermostat (what does this mean? what procedure did you follow?)

There are only two things that I can tell you:
-You need to put G12 in your car, and with the random ratio of water/coolant that you have, you might have to drain the whole system and then fill it up again.
-You need to give us more information.

[BlackLock_A4]

^^ LOL

Here is something that might help.
http://www.audizine.com/forum/showthread.php?t=334436

Eric

[Vince Stark]

Oh my god. Please stop making new threads and just use one thread to chronicle your heat problems. This is what I posted in your last thread, to which you never replied:


If you keep refilling it with water, your system isn't going to be cooling nearly as well as it should be. How long have you been refilling it with water? A year, I think you said in the other thread? That's way too much water and way too little G12. Have you been using distilled water, at least?

I don't know how you got on the track that your heater core needs to be replaced or flushed, you haven't given nearly enough information in any of the 4 threads you have started for a consistent or coherent diagnosis from the AZ members.

1. Does your coolant temperature gauge work?
2. Does it rise and stay put at 1/2 way (completely vertical) like it should when working properly?
3. Do you have overheating problems?
4. Have you looked around the engine bay from the top, with a flashlight and with all the covers removed, immediately after driving to look for leaks?
5. Have you looked around the engine bay, from the bottom, with a flashlight and with the bellypan removed, immediately after driving to look for leaks?
6. Have you gone to an Autozone or met up with anybody who has VAG-COM to get scanned for codes?

The only things you have told us are that:
-You have no heat
-You tried bleeding air from the system (what procedure did you follow?)
-You tried playing with the thermostat (what does this mean? what procedure did you follow?)

There are only two things that I can tell you:
-You need to put G12 in your car, and with the random ratio of water/coolant that you have, you might have to drain the whole system and then fill it up again.
-You need to give us more information.

what he said/\/\

[S4NORICE]

Not realy sure why pulling the hoses off the core connections was so difficult. It takes about 30 seconds..

Simple way to tell if its the core is this: Start the car and let it warm up to temp with the climate control (cc) tuned off. Once your engine is up to temp, turn cc temp up to HI, but only turn the fan on 2-3 bars. Put your hand on the vent and rev the engine to about 2500-3k and hold the rpms for about 30 seconds. If your core is semi clogged you will feel air get warmer due to your water pump spinning faster providing more flow to the core. If you feel absolutley no change in temp, then I think you should look elswhere. Again, Do not turn the fan on HI to perform this test.

Based on my experience, while driving, a semi clogged core will put little a bit of heat while driving, but then the temp will drop right off while sitting at idle at a traffic light...


Flushing with just water isn't gonna get you very far. Like the thread above says, Whatever is clogged in the core needs to be broken down with chemicals. I didn't have any luck with compressed air, it didn't do jack shit...

I had to flush my heater core on 4 seperate occasions in order to save it. Each time, I flushed it repeatedly over the course of about 5 hours or so. Each time I flushed it, it would get a bit better. I used everything from, degreaser, to lime away, to drano, to gunk radiater flush - etc etc. I even heated the fkn drano & lime away up on my stove before I dumped it into the core to let it break the shit down beter...

Bottom line, I went from almost zero heat to HOT heat. Sure, it took some time, but was certainly a lot easier than replacing the core. That was last resort.

[S4NORICE]

I also agree with everything that everyone else stated above. So before you point your finger at the heater core, do what I mentioned above.

[audinaut]

Not realy sure why pulling the hoses off the core connections was so difficult. It takes about 30 seconds..

Simple way to tell if its the core is this: Start the car and let it warm up to temp with the climate control (cc) tuned off. Once your engine is up to temp, turn cc temp up to HI, but only turn the fan on 2-3 bars. Put your hand on the vent and rev the engine to about 2500-3k and hold the rpms for about 30 seconds. If your core is semi clogged you will feel air get warmer due to your water pump spinning faster providing more flow to the core. If you feel absolutley no change in temp, then I think you should look elswhere. Again, Do not turn the fan on HI to perform this test.

Based on my experience, while driving, a semi clogged core will put little a bit of heat while driving, but then the temp will drop right off while sitting at idle at a traffic light...


Flushing with just water isn't gonna get you very far. Like the thread above says, Whatever is clogged in the core needs to be broken down with chemicals. I didn't have any luck with compressed air, it didn't do jack shit...

I had to flush my heater core on 4 seperate occasions in order to save it. Each time, I flushed it repeatedly over the course of about 5 hours or so. Each time I flushed it, it would get a bit better. I used everything from, degreaser, to lime away, to drano, to gunk radiater flush - etc etc. I even heated the fkn drano & lime away up on my stove before I dumped it into the core to let it break the shit down beter...

Bottom line, I went from almost zero heat to HOT heat. Sure, it took some time, but was certainly a lot easier than replacing the core. That was last resort.

That's some really good info based on first hand experience But for $130 some would just pony up for a new heater core and be done with it.

The OP still has not replied that he has inspected the plastic plug in block near connection for thermostat housing as I asked here....clicky.

This plug has a TSB on it -- TSB #2009949/3, dated March 26, 2007. Noteworthy text of this TSB that applies to OP's symptoms are:

• Coolant Leak or No Heat in Passenger Compartment From HVAC System
  
• Customer concern of loss of coolant, but no leak in cooling system can be found.
  Customer concern of no heat or noticeable drop in heat output in passenger compartment from HVAC system when engine at idle.
  Both concerns may be caused by a coolant leak from plastic plug.
• Other than loss of coolant, a leaking plug can cause air to enter into the cooling system and reduce the effectiveness of the passenger compartment heating system.
• Cooling system MUST be tested for leaks with engine cold (below 32°F / 0°C)
• The leak from this plug usually occurs only when the engine is cold (below 32°F / 0°C).
• If cooling system is tested for leaks with engine warm or hot, leaks from this plug may not be detected.
• Coolant leak from this plug can be sometimes misdiagnosed as a leaking coolant thermostat housing. Always carefully inspect suspected areas to detect the actual source of the leak.

Duplicate of this TSB, with repair steps, can be found at bottom of page here.....clicky

[tbmaciii]

1. Does your coolant temperature gauge work?
2. Does it rise and stay put at 1/2 way (completely vertical) like it should when working properly?
3. Do you have overheating problems?
4. Have you looked around the engine bay from the top, with a flashlight and with all the covers removed, immediately after driving to look for leaks?
5. Have you looked around the engine bay, from the bottom, with a flashlight and with the bellypan removed, immediately after driving to look for leaks?
6. Have you gone to an Autozone or met up with anybody who has VAG-COM to get scanned for codes?

As far as my cooling system goes, everything appears fine, except the fact I have to put fluid in it once every 6 months. The gauge never goes above 1/2, never once overheated. The answer to number 4, yes, twice this week. Only leak I found was from the bolt I opened to bleed the air out of the coolant system(the one right under the engine cover on the right side of the block), that wasnt tightened all the way, so I tightened it and it should be good to go. No havent gone to autozone, right now my car doesnt have a gas pedal and im not putting that bitch back on until my heat works bc of how bad it was to get it off.

1. I have a friend with vag-com who is coming to scan the codes
2. I doubt that just because I have a poor mixture of distilled water and G12 that my heat doesnt work UNLESS there is still a clog, but the water runs clear thru it now. I will try CLR today I guess. How much should I pour in?
3. Flushing the coolant system seems like a pain in the ass, is it something I can do or do I need to take it to audi
4. Heat blows out if my fan is turned to only 1 or 2 bars, but when I turn it up higher, cold air comes out

[tbmaciii]

That's some really good info based on first hand experience But for $130 some would just pony up for a new heater core and be done with it.

The OP still has not replied that he has inspected the plastic plug in block near connection for thermostat housing as I asked here....clicky.

This plug has a TSB on it -- TSB #2009949/3, dated March 26, 2007. Noteworthy text of this TSB that applies to OP's symptoms are:

• Coolant Leak or No Heat in Passenger Compartment From HVAC System
  
• Customer concern of loss of coolant, but no leak in cooling system can be found.
  Customer concern of no heat or noticeable drop in heat output in passenger compartment from HVAC system when engine at idle.
  Both concerns may be caused by a coolant leak from plastic plug.
• Other than loss of coolant, a leaking plug can cause air to enter into the cooling system and reduce the effectiveness of the passenger compartment heating system.
• Cooling system MUST be tested for leaks with engine cold (below 32°F / 0°C)
• The leak from this plug usually occurs only when the engine is cold (below 32°F / 0°C).
• If cooling system is tested for leaks with engine warm or hot, leaks from this plug may not be detected.
• Coolant leak from this plug can be sometimes misdiagnosed as a leaking coolant thermostat housing. Always carefully inspect suspected areas to detect the actual source of the leak.

Duplicate of this TSB, with repair steps, can be found at bottom of page here.....clicky

This is what I am walking outside to work on now. Hopefully I can find it

[audinaut]

This is what I am walking outside to work on now. Hopefully I can find it

IIRC, it is not something visually apparent on the block without doing some visual gymnastics. Picking up one of these (the larger rectangular one would work really well in this instance) from any automotive supply shop, while shining a flashlight off it's viewing surface onto the block will help you get a visual on the plug -- clicky linky thingie.

Good luck!

[tbmaciii]

should I look from under or above?

[audinaut]

should I look from under or above?

Above. If you use a telescoping mirror with a flashlight as I described in my last post you should be able to see it. If you unscrew the coolant reservoir and move it aside (lift up from front while hinging it in back, then lift/move at an angle towards front of car) you will give yourself more room to work with.

[tbmaciii]

Im assuming its the thermostat I need to take off to see it?

[audinaut]

hmmmmm......per the TSB, visually inspect the area around the plug? Is there any evidence below it on the block that it is leaking? Again, a mirror will help. Removing the thermostat may be necessary to see if it is bad on the coolant side of the plug -- draining the coolant will be necessary per the TSB instructions. If you go that far, you might as well replace the plug as it is not an expensive item.

Look at this thread......clicky linky thing

[vintagespin]

I was able to see the leaking j-plug by looking between intake runners 2 & 3 (the middle two) underneath the dipstick bracket. The dipstick bracket is pretty much directly blocking your line of sight, but if you do some "visual gymnastics" as audinaut said, with the way you shine your flashlight, you should be able to see the 13mm bolt directly beneath the dipstick bracket, and you should be able to see pretty easily if there's any coolant pooled up or leaking beneath it.

You don't have to remove anything except the engine cover to be able to look at it. It's tricky, but you can find it. It's right next to the thermostat. Or, rather, right "behind" the thermostat if you're looking from the front bumper back.

[tbmaciii]

Audinaut, from what I can see there is no leaks at all around it. I also found I got the best view of it by looking down parallel to the dipstick holder. So I guess I will start researching draining the cooling system and replacing the heater core

[tbmaciii]

I assume I can flush the coolant system but just taking the radiator drain plug off on the lower drivers side. However, whats the deal with making sure all the air is bled from the system?

[vintagespin]

After you drain all the coolant, plug in the sensor again (the sensor is the drain point, on the lower radiator hose). Then do this:

1. Fill up your coolant sytem with a 50/50 mix of G12 + distilled water enough so that it's sitting up to the max line in your reservoir.
2. Take off the bleeder screw cap on the hard line that runs over the intake runners.
3. Let your car idle up to operating temperature.
4. The coolant level is going to start dropping, so start pouring in a 50/50 mix and make sure that it doesn't suck in any air.
5. When a constant stream of coolant starts to come out of the bleeder screw, put the cap back on and button everything back up.

[tbmaciii]

is it best to premix 50/50 then pour? How hot is that "constant stream" of coolant going to be when it comes out. This seems to be a messy operation lol

[vintagespin]

it's not that messy. and look at how small that bleeder screw is. it's more like a constant dribble, without any hiccups for air. and yes, it's really best to premix it 50/50 then pour.

[audinaut]

Coolant needs to flow freely in the system. An air pocket acts like a physical wall to the liquid coolant -- the coolant hits the wall and just stops flowing. An air pocket near the heater core can stop the hot coolant from flowing through the heater core. If the coolant lines in the heater core do not get hot (no hot coolant in core lines, only cold coolant) the heat exchanger has no heat to warm the air crossing over the heat exchanger in the core. Clogged heater core coolant lines also create the same situation in the heater core.

What vintagespin said for bleeding works well. I will add to that to occasionally squeeze with your hand the upper radiator hose while following his steps -- this will help force coolant past any air pockets in the system and move the air pocket to the bleeder valve. Also, raising the coolant reservoir at times with your hands so it is higher by 6 inches or so than it normally sits, while tilting it slightly so the bigger hose in front points more to the ground, will help move coolant into the system. The engine must get the coolant hot to properly bleed the system. Here is another way to bleed the system......clickyclick. Also know, that multiple cycles of the above bleeding methods, letting the coolant cool and get hot , may have to be done to properly remove any air pockets from the system.

Tips.....put a rag or something around the bleeder valve to catch the hot coolant that comes out of it. Also, if you have not filled the coolant system up yet, I would just run straight distilled water in the system until you can get the heater working as you want it. Once get the heater working properly, drain the water from the system at the lower radiator hose and refill and re-bleed with 50/50 mix of coolant. You will not be able to drain all the distilled water from the system, but adding in a 50/50 mix will still keep you within a final 60/40 water/coolant mix which is fine. Using straight distilled water for now will be easier/cheaper than using new coolant again if you go after the heater core later. Also, the use of straight water then draining it will further flush the system for you. But, don't leave your system filled with water overnight! It will freeze and crack your block!

I've re-read this thread. I'm trying to understand where you are at right now. I read that you have drained the coolant from the car, back flushed the heater core, and refilled the coolant system. Is that right? If that is where you are at, I'd re-bleed the system as we've suggested to eliminate the possibility of any air pockets in the system before going after the heater core. If you feel confident you've done the bleeding right, and you want to replace the heater core, drain the system replace the core and the J-plug and o-ring (its cheap and easy insurance against future failure and you have the coolant drained out of the system).

[audinaut]

Another tip.....

If you have the coolant reservoir tight, and the car reaches operating temperature, do not open the reservoir cap until the car cools down, otherwise you will have coolant come out of cap when you loosen it! By opening the cap, you are releasing the built up pressure in the system out through the cap, and the coolant will follow the pressure release.

You do not have to remove the release valve on the hardline during bleeding. You only need to loosen it a bit until the air/coolant start coming out. The more you open the valve, the more will escape from it.

[mayhem]

If you have a very high ratio of water in your coolant system, its jsut a matter of time before it freezes and cracks something on you. You should drain it and refill it with the proper 50/50 G12/water mix and burp it to get the air out of the system.

Question, have you checked the temperature of all 4 underhood hoses? When the car is warmed up, grab each hose in turn and see if they're all hot...each of the hoses (radiator inlet, outlet, heater core inlet, outlet) should be hot enough that you seriously do NOT want to hold them wiht your bare hand for more than a few seconds. If any one hose is cool, you need to find out what is blocking the flow of coolant through that hose.

When you flushed the heater core, did you flush it in both directions? I had a similar problem in my 2000 Chevy Silverado. Heater core got plugged up with crap and the heat stopped working. I removed both hoses and ran a garden hose through there repeatedly alternating the flow. I got a bit of grit out of the forward flush, but when i reversed direction it blew out all the crap that was being held inside the core by the flow of coolant...it looked like a pot of coffee grounds came out. A bit more back and forth and I was good as new. No CLR or other treatments were necessary in the case of my truck, but the blockage was a mass of loose amterial that comes from the breakdown of the extended use DEXcool thats was in there from the factory...the breakdown of fluid in an Audi might very well leave hevay, sticky deposits in the heater core and radiator.

[tbmaciii]

You guys have been very helpful.

I have not checked the temp of the hoses, I will do that now. However, when I took the 2 hoses going to the core off, there was maybe 1/2 cup of fluid that came out combined. Is that a sign of maybe there is a block there?

Im nervous that if I flush the system, bleed it. There will be a leak somewhere if there is one now. I feel like I shouldnt have to be filling my resevoir 2 or 3 times a year

[audinaut]

....when I took the 2 hoses going to the core off, there was maybe 1/2 cup of fluid that came out combined. Is that a sign of maybe there is a block there?

No. After draining the coolant at the lower radiator hose, you will still find coolant in a number of hoses/connections of the system. Draining does not remove all the coolant from the system, just a lot of it.

Im nervous that if I flush the system, bleed it. There will be a leak somewhere if there is one now.

You want to find any leaks and get them fixed. You don't want to find a leak in the midst of driving across Death Valley in the summer or across North Dakota in the winter.

I feel like I shouldnt have to be filling my resevoir 2 or 3 times a year

There are quite a few reasons why you may have to add coolant. Many of them attributed to just the age/mileage on your engine, how hard previous owners were it, and how well they may, or may not, have taken care of it.

FWIW, I have started a regime of flushing and putting new coolant in my car yearly. Regardless of what Audi claims, coolant is not a lifetime fluid only requiring topping off occasionally. I'm electing to flush/re-fill annually to avoid potential problems such as yours due to old/deteriorated coolant in the system. The low expense of new fluid every year, with the hour of time that goes with it, is worth the extra piece-of-mind for me.

[tbmaciii]

No. After draining the coolant at the lower radiator hose, you will still find coolant in a number of hoses/connections of the system. Draining does not remove all the coolant from the system, just a lot of it.

You want to find any leaks and get them fixed. You don't want to find a leak in the midst of driving across Death Valley in the summer or across North Dakota in the winter.

I havent flushed the system yet. That was initially when I took the hoses off of the core at the firewall before doing anything at all, so the system is still full of coolant

[tbmaciii]

Audinaut, warmed my car up for 10 minutes, turned the fan on blast. The bottom has going to the core has warmed up to be relatively hot, not to hot to touch tho. The top hose is cold. This a sign of anything? Maybe I have a bad heater core itself

[audinaut]

Audinaut, warmed my car up for 10 minutes, turned the fan on blast. The bottom has going to the core has warmed up to be relatively hot, not to hot to touch tho. The top hose is cold. This a sign of anything? Maybe I have a bad heater core itself

YGPM.

No heat in the cabin? What did your temp gauge in the cluster do before you got into this? What does it do now? What are your radiator fans doing? Are they working normally or working too much? Scanning for DTC codes would be helpful to rule out either ECT sensors.

You have to bleed the system (see previous posts) to insure you have no air pockets -- this is important to rule out. I PM'd you another doc on how to install a new heater core. Inside the doc is a procedure on how to bleed the heater core at the intake hoses -- you may want to try that next, as you could have an air pocket in/near the heater core that cannot escape via the bleeder valve on the hardpipe. If you feel you've done the bleeding successfully, then absent other symptoms, back flushing (see previous posts) or replacing the heater core would be next.

[audinaut]

Audinaut, warmed my car up for 10 minutes, turned the fan on blast. The bottom has going to the core has warmed up to be relatively hot, not to hot to touch tho. The top hose is cold. This a sign of anything? Maybe I have a bad heater core itself

You have the accelerator pedal disconnected, right? So the car ran for 10 minutes at idle only? And the cluster temp gauge went to the middle of the gauge? Bentley calls for the RPM's to run at 2K RPM's for about 3 minutes to bring the coolant up to operating temp. You can temporarily put the accel pedal back with two of the three bolts only -- I know that third bolt is a bitch to get back in.

[tbmaciii]

To remove the heater core I had to take this Orange circular clip assembly off of the brake pedal rod, I put it back but the brake light wont go off now? WTF?

[S4NORICE]

That's some really good info based on first hand experience But for $130 some would just pony up for a new heater core and be done with it.

The $130 bucks for the heater core was not the problem, lol.. Flushing is very easy when its isolated from the rest of the system, I never removed the core.... The hose connections go straight thru the firewall, I just diconnected the hoses from under the hood, then attached clear tubing to the core connections and flushed it from thr...

Pulling the dash is a bit more difficult. When I mentioned the 5 hrs a flush thing, 95% of that time was letting the chemicals sit in the core to break the shit down.

[S4NORICE]

Regardless of what Audi claims, coolant is not a lifetime fluid only requiring topping off occasionally.

Amen.

[S4NORICE]

To remove the heater core I had to take this Orange circular clip assembly off of the brake pedal rod, I put it back but the brake light wont go off now? WTF?

Are you refering to the brake light on your instrument cluster, or do you mean the brake lights on the back of the car?

[audinaut]

To remove the heater core I had to take this Orange circular clip assembly off of the brake pedal rod, I put it back but the brake light wont go off now? WTF?

Hate to tell you, but I think you may have FUBAR'd the brake pedal switch for the pedal.

The switch has a very "unique" procedure in how to take it off and put on the pedal that involves whether the switch plunger is in the compressed or un-compressed position, and turning the switch 45 degrees when seated, with the brake pedal either in the fully up or down position depending on which version of the switch part number you have. If you deviate from the correct procedure for your brake switch, you can FUBAR it.

Take a pic and post it up along with the part number on the side of the switch. I'm thinking your part number will be 3B0 945 511A.

[S4NORICE]

4. Heat blows out if my fan is turned to only 1 or 2 bars, but when I turn it up higher, cold air comes out

The reason why you have heat with the fan on low is because their is hardly any fluid flowing through the core. The more air you put past a heater core, the more fluid flow you'll need to heat that air......... A small amount of air only needs a little bit of fluid flow... Thats exactly why I said test it with the fan speed on low...

[mayhem]

Audinaut, warmed my car up for 10 minutes, turned the fan on blast. The bottom has going to the core has warmed up to be relatively hot, not to hot to touch tho. The top hose is cold. This a sign of anything? Maybe I have a bad heater core itself

You are not getting proper fluid flow through the core. Try the procedures that have been mentioned already about 30 times to get some chemical cleansers in there and then flush it all out in both directions, reconnect, refill, burp out all the air (also mentioned several times) and try it again. If that fails then your core is too plugged up to be cleaned out and you'll need to replace it.

[tbmaciii]

Hate to tell you, but I think you may have FUBAR'd the brake pedal switch for the pedal.

The switch has a very "unique" procedure in how to take it off and put on the pedal that involves whether the switch plunger is in the compressed or un-compressed position, and turning the switch 45 degrees when seated, with the brake pedal either in the fully up or down position depending on which version of the switch part number you have. If you deviate from the correct procedure for your brake switch, you can FUBAR it.

Take a pic and post it up along with the part number on the side of the switch. I'm thinking your part number will be 3B0 945 511A.

I will take a pic tommorow and post, im at work for 24 hours today. I wonder if it can be fixed or I have to replace it. Ive searched online but nothing.

Its my actual brake lights that wont go out, not the light on the cluster. So I just unplugged it.