Please help! I live in the chilly Midwest! I need heat!

Well, I bought my allroad with about 80k miles on it after wrecking my A6 Avant 3.0Q... I really like the allroad a lot more, but I am experiencing a lot more problems. My biggest problem is the I need to replace the torque converter. At the moment though, I need to get the heat fixed since it is winter & I have very limited ability to defrost the windows. The heat doesn't work at all at any engine speed, wether highway driving or sitting at idle. Everything else seems fine, but this has been an ongoing problem. The AC actually works, but nowhere near as good as it did on my A4 & A6 did.

FYI, my AR currently has about 103,000 miles...

Is this the fan diverter problem I've read about? I've read some vague comments about this, but haven't seen anything that seems to expand on it.

Thanks,

Airwalk

One more thing... If I'm driving with the environmental system completely off, & turn it on, it blows warm air for about 10 seconds. Then, it just blows cool air. I have been running the system on "HI" as well.

Could be blend door, air bubble in heater core, heater core plugged, or thermostat stuck open. Do a search. It's been discussed several times here and in the A6(C5) forum.

Could also be a problem with your climate control unit.

Start eliminating problems one by one or else take it to the shop. You definitely need heat.

Is the engine temperature normal, or does it stay cool?

Do you have heat when not driving, just idling?

Could also be a problem with your climate control unit.

Start eliminating problems one by one or else take it to the shop. You definitely need heat.

Is the engine temperature normal, or does it stay cool?

Do you have heat when not driving, just idling?

I get no heat. Period. I've had it in the shop, but my mechanic said everything is normal... To him, that means everything that isn't automated. He's an old curmudgeon. :-)

The engine temp does stay normal & no, the air is cold wether I'm driving or idling. It does seem to work better(barely luke warm) if I don't use the heat on "auto" & just set the fan speed to about 3 notches up. If I set it to auto, it just blows real hard, but only cold air.

I am also seeing a lot of foam up on the dash... Likely coming from the defrost vent? When I saw this, I assumed there might be a blockage? Or did the blend door motor get jammed by the foam? I'm very unfamiliar with this system in the car as this is the first time I've ever had this problem... I've had an A4, A6Avant & now this Allroad. So, I know how hot the heat can blow.

Also, since my AC seems mediocre...???

If both the lines going into the firewall to the heater core are hot, then it is more likely a climate module or blend door problem. Mediocre A/C would point to this as well.

I assume that the A/C problem is in the summer. The A/C won't work when it gets too cold outside.

If both the lines going into the firewall to the heater core are hot, then it is more likely a climate module or blend door problem. Mediocre A/C would point to this as well.

I assume that the A/C problem is in the summer. The A/C won't work when it gets too cold outside.

Yes, thanks for your help. I believe the problem is definitely narrowed down. I'll check everything, but I'm pretty sure it's either the control or the blend door.

You are right, the AC problem is in the summer... It works better than the heat, but neither the heat nor AC work as they should. Thanks again.

Does anybody have any good advise as to how to access the blend door motor in a 2003? I thought I read that I could get to it through the glove box...

FYI, the lines coming from the heater core are both nice & hot. So, I'm steering toward the blend door motor. If that's not it, maybe the thermostat or vacuum. I'm trying to fix the easiest thing first! I'll keep everyone posted!

Blend doors motors are behind the glove box & look to be working well.

Since I've been going thru this recently, I'll throw in my $.02 to a fellow midwesterner (although I'm an East Coaster now):

I've posted on this exact thing ad nauseum for the last 3 months (search my posts) since I've been a new allroad owner.

The problem is most likely a blocked/clogged hearer core, especially if "everything" else checks out. The reason you're getting a momentary blast of warm-ish air is because the hot coolant will slowly and reluctantly flow thru your clogged core, but as soon as you extract the heat off by turning on the blower, the coolant doesn't circulate with enough volume, or fast enough, to replenish the core with new, hot coolant. So your heat remains tepid and pathetic.

If you find some other reason, or come up with a fix, PLEASE let us all know, because there are several of us watching these "heater" posts for a cure other than a core swap. Unless I read of some other cause, I'm swapping the core myself after i survive this winter.

Since I've been going thru this recently, I'll throw in my $.02 to a fellow midwesterner (although I'm an East Coaster now):

I've posted on this exact thing ad nauseum for the last 3 months (search my posts) since I've been a new allroad owner.

The problem is most likely a blocked/clogged hearer core, especially if "everything" else checks out. The reason you're getting a momentary blast of warm-ish air is because the hot coolant will slowly and reluctantly flow thru your clogged core, but as soon as you extract the heat off by turning on the blower, the coolant doesn't circulate with enough volume, or fast enough, to replenish the core with new, hot coolant. So your heat remains tepid and pathetic.

If you find some other reason, or come up with a fix, PLEASE let us all know, because there are several of us watching these "heater" posts for a cure other than a core swap. Unless I read of some other cause, I'm swapping the core myself after i survive this winter.

Thanks for the reply... Now that I've gone thru past maintenance records on this car & the thermostat was replaced about 5k miles before I bought it... I'm not gonna even go down that road. I'll sell this thing before I pull the front end off again!

So, are you saying that even though my heater lines are both hot, that the core could still be clogged? I get no heat at any engine speed.

Also, I'm starting to have trouble with the air suspension & my torque converter. This car will be sold as soon as I can sell it... Any takers?

Since I've been going thru this recently, I'll throw in my $.02 to a fellow midwesterner (although I'm an East Coaster now):

I've posted on this exact thing ad nauseum for the last 3 months (search my posts) since I've been a new allroad owner.

The problem is most likely a blocked/clogged hearer core, especially if "everything" else checks out. The reason you're getting a momentary blast of warm-ish air is because the hot coolant will slowly and reluctantly flow thru your clogged core, but as soon as you extract the heat off by turning on the blower, the coolant doesn't circulate with enough volume, or fast enough, to replenish the core with new, hot coolant. So your heat remains tepid and pathetic.

If you find some other reason, or come up with a fix, PLEASE let us all know, because there are several of us watching these "heater" posts for a cure other than a core swap. Unless I read of some other cause, I'm swapping the core myself after i survive this winter.

Same problem here (well, I get heat only when at >2K RPM) on my '01 A6 2.7T. Just curious why you need to do a core swap if it's blocked/clogged. Have you tried to do a flush similar to what's done in the tech article for an A4 (in the A4 "Engine" section, titled "Heater Core Flush"... sorry I can't link directly to it)? http://www.audiworld.com/tech/

I haven't done this yet, but I plan to and hopefully fix my issue. Maybe the flush only applies to the A4... let me know if I'm missing something here.

if both of your heater lines are hot when running the core is not clogged, not completely anyway.

I don't have time to search now but you can access diagnostic program on climate control by pressing some two buttons together, it will show you all temp sensors outputs etc which might be the issue with your car. If for example heaer core temp sensor is shut and shows cold all the time, the system will never enable heat. Just search the forums or even better google for this.

It is also possible that some output functions cam be acxtivated with vag-com/vcds so that you can determine what's not jiving in the system.

I would flush the core, then the engine before anything else. Be sure to properly bleed the system as you refill it. There are 2 bleed ports in the system. One is actually on the heater hose connection, can't remember inlet or outlet. You pull one of the hoses halfway off, and it will reveal a small hole that will allow air to escape as you fill it. The other is towards the front of the motor, next to the drivers side of the power steering pump. It's a pain to find.

One other trick is to remove the coolant res and lift it as high as possible when filling the engine. It adds a little more force to help remove air. Raising the front of the car may also help slightly.

Steve

if both of your heater lines are hot when running the core is not clogged, not completely anyway.

I don't have time to search now but you can access diagnostic program on climate control by pressing some two buttons together, it will show you all temp sensors outputs etc which might be the issue with your car. If for example heaer core temp sensor is shut and shows cold all the time, the system will never enable heat. Just search the forums or even better google for this.

It is also possible that some output functions cam be acxtivated with vag-com/vcds so that you can determine what's not jiving in the system.

Thanks. This is about where I'm at. I've been troubleshooting this all day & I'm at a loss. Everything I've checked is working good... I had a brain fart about the thermostat! It's been replaced before & judging by the fluid temp & other indications, it's working good. I finally bothered my mechanic & he also eluded to this button pushing method. I do not have a scanner or vag/com, so I'm doing this in the stone age. I'll do a search about this method, but at this point, I'm clueless.

Like I mentioned before, I've been posting about this ad nauseum and i have YET to find anyone who has reported a heater core temp sensor problem that was the cause of their no-heat condition, when reporting the same symptoms we all are. Again, if anyone comes across a cause OTHER than the core itself, please report it!

I have flushed my core myself six ways from Sunday, then had a shop flush it and the whole system, and bleed the **** out of it; and it STILL would not flow coolant in the correct direction; I had to swap hoses to get it to flow at all, and both of my hoses now are hot to the touch at the firewall, yet my heat at the defrosters and floor is warm at best. It WILL get hotter as the outside ambient temp rises, which only indicates that what hot air IS coming off the core by the blower motor isn't being cooled as fast as it travels thru the heater box.

I believe that the continued gunk that comes out with every flush indicates that the interior is coated with years-old coating, and is NOT ALLOWING HEAT-TRANSFER FROM THE COOLANT TO THE FINS, AND THEN TO THE BLOWER AIR. This is why the core feels hot at both hoses at the firewall, but no real heat into the cabin. You mechanical engineers that remember your heat-transfer classes from college check me on this.

I still stand by my inefficient heater-core theory, only really corrected by a core swap.

Brider, it sounds like your system might have a similar problem as mine. I would think that I would at least get some warm air, but I only get cold air. Period. I'm begining to wonder if my blend door is broken or jammed.

The system works perfectly as it should... It just blows cold air. For instance, if I set the system to "auto" it doesn't blow hard until the heater core warms up... Just as it should. If this didn't happen, I would suspect that the heater core wasn't getting warm enough, but it is. I've checked everything else, & I'm at a loss. The other problem could be a sensor somewhere???

I'm now trying to decide if I want to tear apart the dash to see if a blend door could possibly be jammed or broke. Or if there is a broke sensor... Quite honestly, I think I'll just bundle up for the rest of the winter... I've got bigger fish to kill.(torque converter!!!)

I'm seriously trying to figure out why in the hell this car is so popular. It's most definitely overrated.

I don't know anything about a "heater core temp sensor". If it does exost, I would have THOUGHT that the shop I took it to to FIX the no-heat condition would have checked it and confirmed to me that it was good.

My understanding was that on AUTO, the fan blower would begin to come on as the ENGINE temp came up, not the heater core temp. If that's the case, my theory about the heater core not transferring heat is still valid.

Good luck, let us know if you check the blend door motor.

Not to rub it in your face, but your TC problem is why I bought a 6-sp. Still, I'm no fan of constant shifting, I WISH I was driving an auto.

I don't know anything about a "heater core temp sensor". If it does exost, I would have THOUGHT that the shop I took it to to FIX the no-heat condition would have checked it and confirmed to me that it was good.

My understanding was that on AUTO, the fan blower would begin to come on as the ENGINE temp came up, not the heater core temp. If that's the case, my theory about the heater core not transferring heat is still valid.

Good luck, let us know if you check the blend door motor.

Not to rub it in your face, but your TC problem is why I bought a 6-sp. Still, I'm no fan of constant shifting, I WISH I was driving an auto.


Well, I don't know anything about the sensor either... I'm just relaying information I've read. Your theory makes more sense. I'm gonna flush it tomorrow & see what happens. I wish I would've known more about the TC issue too, but my other car was wrecked & I got a descent deal on this one. Just FYI.

heater core & now I have heat. The mechanic said the likely cause was that somebody used the wrong coolant & it gums up the system... Really? I asked him about the temp of the in & out pipes on the heater core & his opinion was that they should be much hotter than they were.

I know that the manual says to use G12, but can this gummed up problem really happen? Or is it a corrosion issue? If anyone who has ever swapped a heater core has any insight, that would be some good info. To my knowledge, G12 is all that has ever been put in this car. The fluid looks about as orange as it could be. Anyhow, maybe it's the G12 that causes the problem!

Glad to finally have heat, although it's nowhere near as hot as it could be!

Talk to someone who knows about the chemistry of metals. You have a cooling system that is a bi/tri-metal environment immersed in a water based solution. I'm quite sure that Audi knows this and has done their homework. It is MHO that the issues with the cooling systems on these cars are probably due to the use of non-G12 coolant.

heater core & now I have heat. The mechanic said the likely cause was that somebody used the wrong coolant & it gums up the system... Really? I asked him about the temp of the in & out pipes on the heater core & his opinion was that they should be much hotter than they were.

Glad to finally have heat, although it's nowhere near as hot as it could be!

...I am VERY interested in how LONG your current heating capacity lasts. We may just be able to establish a set of symptoms verifiable by several users in order to predict the REAL cause of our problems to future sufferers.

My heat "came back" to some extent after I, and then the shop, flushed my core. I myself collected TONS of sandy and flaky crap into my flush bucket, and the shop soaked it for a while in cleaning solution before their final flush.

Heat came back (only when swapping heater hoses at the core), but that was a couple of months ago, and now at 20 deg outside, I can't tell if it's diminished again, or just wasn't really up to the task after all that work to begin with.

You took the first obvious step and I hope it works out for you!

Is is possible to snake the heater core? Or at least part of it? Would a radiator shop be able to do something? Pressure washer maybe? Just shooting wildly at ideas.

No one has gone so far as to swap the core yet, have they???

I think the C5 A6 forum has a bit "better" info on the heater woes, and there's a guy there who HAS swapped cores, and says it's not the end of the world, very do-able, just a bit involved, and most of us get scared away when we have to deal with interior panels and such, plastic breaking, clips lost, forgetting where plugs go, etc. But I'm going to suck it up and do it this summer.

Is is possible to snake the heater core? Or at least part of it?


Absolutely not....flat, very close tolerance passages, for maximum heat transfer efficiency...the same thing that lets em clog so easily IF something really stupid is done, like ever using stop-leak or ever mixing ANYTHING (no matter what the label claims) with G-12.

the heat has been working good enough to keep me satisfied. It's still no where near as hot as my A4 1.8T & my A6 3.0 were, but I'll get by.

Anyhow, this is off the subject, but I did get the torque converter replaced... I bought one from 517 Transmissions. They had very fast shipping & a reasonable price. I sent the core in today so that I could get my $300 back. I am happy so far since the dealers quote was $3600!!!! I had the new one put in by a local shop who specializes in after market upgrades to VW products. I was only charged $600 labor + $48 for fluids! So, I'm looking at a grand total of about $1252 for the total cost! I'm very happy with that. My normal mechanic, who is very good wanted about $1700 for the labor(he was quoting rack rate + what the book says as far as how long it will take). Anyhow, if you are in the northern Illinois area, go to Autohaus in Machesney Park. Tim is very fair & knowledgable about Audi/VW cars. He knew about how long it would take him & quoted me $600 labor before doing the job. When I picked up the car, he stuck with that price. Nice guy! Highly recommended!

I'm likely going to be doing airbags next... I've talked with him & again, he quoted me an awesome price & also offered to change the ride height if I wished for that. I'll do some research before I decide on that change... I don't want to drastically change the comfort of the ride.

The heaters in these cars will get clogged up IF its had coolant issues, like mixed coolant, hard water mixed in the coolant or any other debris from major service work performed in the past. These cars need to use G12 or G12+ coolant mixed with distilled water for long term performance and to prevent any build up. Also, if you have a clogged heater core, the heater hoses need to be bypassed and the system ran with the heater core to allow any debris to bypass the heater circuit. I would then pull the thermostat out and the radiator hoses and back flush the entire cooling system and lines with tap water to remove any debris or crude in the system. I have seen new heater cores get clogged within days of installation because there's crude trapped in heater coolant circuit. Once the flow diminishes through the heater core, the remaining crude stays in the lines. If you install a new heater core, the remaining crude in the system flows right into a free flowing heater core and clogs is shortly after. Some have had success also by using a bucket, pump and some hoses and running CLR backwards through the original heater core for an hour or so to clean up the heater core. This should remove a mineral deposits in the core and bring the heat back where it should be. All in all, when adding or replacing coolant, use the correct coolant and get some distilled water. You will appreciate it in the long run.

[QUOTE=ezveedub;24262982] Also, if you have a clogged heater core, the heater hoses need to be bypassed and the system ran with the heater core to allow any debris to bypass the heater circuit. I would then pull the thermostat out and the radiator hoses and back flush the entire cooling system and lines with tap water to remove any debris or crude in the system. QUOTE]

This sounds rational, and is the general idea to attach a garden hose (using one of those Prestone hose-attach couplings, somehow)to the system and flush everything out thru a low point, like the bottom of the radiator?

Ezeedub,

I am running only G12 & distilled water. I bought the car with 81,000 miles, so I can't speak for what was put in it before I bought it. I didn't run CLR through it, but I will when winter goes away & I have the patience. As for now, it's keeping my windshield clear & me warm.

[QUOTE=ezveedub;24262982] Also, if you have a clogged heater core, the heater hoses need to be bypassed and the system ran with the heater core to allow any debris to bypass the heater circuit. I would then pull the thermostat out and the radiator hoses and back flush the entire cooling system and lines with tap water to remove any debris or crude in the system. QUOTE]

This sounds rational, and is the general idea to attach a garden hose (using one of those Prestone hose-attach couplings, somehow)to the system and flush everything out thru a low point, like the bottom of the radiator?

I would say to just disconnect the hoses at the heater core and put a garden hose into heater hose that has the bleeder hole. No need to install a flush kit. No need to modify your heater hoses for a simple flush out. I would also remove the lower radiator hose or better, remove the thermostat and flush the block with running water. Remove the top radiator hose and also flush the block from the top hose also and also the radiator.

As for the heater core, you could get some extra regular heater hose and connect it to the heater core and fill it with CLR and let it soak. Just make sure its filled, so attach two hoses to it and hold them upwards higher than the heater core ports so you can allow the CLR to completely fill the core and let it soak. Then flush it out in reverse flow with a garden hose. If you have access to compressed air, I would give it a few blasts in reverse flow also before reconnecting it back to the cooling system. Then see if the heater core performance is improved. Just make sure you flush out all of the CLR before hooking it back up. You don't want that stuff flowing through your coolant system.

The inlet hose (Bottom) on my 2005 Allroad 2.7T was hot, but the outlet one (top) was not. Same heat issue. Removed the battery to get full access to the hoses, unsnapped the thermal cover, worked them off the pipes and flushed the core with a garden hose and sprayer. No discolored crap came out. I used compressed air to blow the remaining water out from the top thru the bottom, reassembled and let the engine warm up - problem solved. I think my issue was excess air, as I had replaced the aux coolant pump in July 2012 and did not perform a full system flush and refill. Note, mix your G12 coolant with distilled water, not water from the tap.