Heater Not Working Properly

Hello

First I need a little more specific on your vehicle to better assist you. Is your model just an A4, or A4 Cabriolet, A4 Quattro Cabriolet, A4 Quattro Sedan, A4 Quattro Wagon, A4 Sedan, A4 Quattro only? Also what is your engine size in liter and the 8th digit of your VIN.

Next, at idle normal operating temperature are the heater hoses going into the firewall both hot or only one?

When the RPM is raised, same question, are the heater hoses going into the firewall both hot or only one?

Has there been anything wrong with your engine temperature at all?

And again, you started having this heater problem “then” you changed the thermostat and you still have the problem?

Do you have Dex-Cool or another brand of antifreeze in your vehicle?

This guide will help us

https://www.2carpros.com/articles/car-heater-not-working

Please answer/do the above and get back with me and let’s see if we can get you some steady heat.

*Vehicle Info: A4 1.8T, 4 Door CVT Automatic.
*8th digit of VIN is E.
*Nothing wrong with engine temperature.
*I changed thermostat after having this problem.
*Car has 18,000 miles.
*I use Audi G12 antifreeze in car.
*At idle only one hose is hot.
*When RPM raised both hoses get hot.
*My engine light is not on. I called Auto Zone and they told me they can't pull the codes if the engine light is not on.

Hello - LeahB Wow, thanks for the outstanding update/information. We don't always get the info we ask for so detailed. Okay, just a few things based off of what you have said. First, there is a Technical Service Bulletin (TSB) out on a similar thing. I have attached that for your review. It actually states: "Customer concern of no heat or noticeable drop in heat output in passenger compartment from HVAC system when engine at idle" This is due to the plastic plug as shown. I put the TSB at the end of this. Next - on the pic below there are two hoses between numbers 1, 2, 13. At idle, is the hose between 1 and 13 the one that is hot and 1 and 2 the one that is cool?

I would first check the plug that the TSB talks about. Even try and replace and see what you have. Next - I would back flush the heater core. If that doesn't work then you may have to replace the core. I am hoping it is just the plug from the TSB and worst case, a back flush if not the plug. You don't have a lot of miles - that is about 6,000 a year...not much driving. Looks like you may have some recalls on your vehicle. The dealer may fix these for free. Please contact the dealer service department, give them the VIN number of your car and have them check on these to see if they apply to you. I have attached those at the end. Last, for Auto Zone etc...sometimes your car can throw a code, the light flash and go out. You might consider that when talking to them in the future. 19 07 01 March 26, 2007 2009949/3 Supersedes Technical Service Bulletin Group 19 number 05-03 dated Apr. 8, 2005 due to revision of a part number.

Vehicle Information Coolant Leak or No Heat in Passenger Compartment From HVAC Condition Coolant Leak or No Heat in Passenger Compartment From HVAC System Technical Background

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.

Plug is installed in engine cylinder block near connection for thermostat housing (arrow). Improved Coolant Plug. Service 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) (see ElsaWeb Repair Manual, Engine Mechanical, 19 Engine Cooling, " Cooling system, checking for leaks "). Tip: 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. Tip: 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. ^ Carefully inspect area where plug is located. If the plug is found to be leaking: ^ Remove and replace the plug. Required Parts and Tools ^ Remove sound insulation below engine. ^ Drain coolant (see ElsaWeb Repair Manual, Engine Mechanical, 19 Engine Cooling, " Cooling system, draining and filling"). ^ Remove upper engine cover. ^ Unfasten coolant reservoir and move to aside. Electrical connector of coolant level sensor must be unplugged. It is not necessary to remove coolant hoses from coolant reservoir. ^ Remove oil dipstick bracket bolts (2x). ^ Carefully remove upper dipstick tube (orange plastic) Ensure that the O-ring on lower steel tube is not lost when tube is removed). ^ Remove bolt from plastic plug. ^ Remove plastic plug from engine block . ^ Install a new plastic plug and secure with bolt to engine block. Fastener torque = 23 Nm. ^ Reassemble dipstick tube and coolant reservoir. ^ Use the VAS 6096/1 to refill and bleed the cooling system (see ElsaWeb Repair Manual, Engine Mechanical, 19 Engine Cooling, "Cooling system, draining and filling" for details and approved coolant antifreeze). When refilling engine with coolant: ^ Always ensure that any trapped air is bled out of cooling system (including heater core). ^ Recheck for leaks on cooling system (see ElsaWeb Repair Manual, Engine Mechanical, 19 Engine Cooling, " Cooling system, checking for leaks"). ^ Reinstall sound insulation below engine. ^ Reinstall upper engine cover.

Warranty Required Parts and Tools Plug - Part No: 06B 103 033 A Tip: Part numbers listed in this bulletin are for reference only. Always check with your Parts Dept. for the latest parts information.

Hello carpros...

I'm having the same issues as stated above. No heat in idle and some heat during hi RPMs. Im not sure if the plug has been changed in this car.

Hose between 13 and 1 is hot. Hose between 1 and 2 is not.

I did flush the heater coil already.

Please any advice will be greatly appreciated..

lvmora

I have a 2001 Audi A4 that the heater is not working. I've adjusted the temperature up/down and I can hear solenoid/valve/door moving. That tells me that the electronic temp. controller is probably working. Do I have a bad heater core or is there something else wrong?

is the radiator full of coolant?
are the heater hoses going to the heater core hot at the firewall?
if they are not then the thermostat is stuck open. if the inlet hose is hot and the outlet hose is cold or luke warm, then the heaer core is stopped up.
hope this helps.

Hi,
My car doesnt blow any hot air. the air conditioning works and when i turn the heaters on they blow hot air for about 30 seconds and then it blows cold air. any idea wats going on?

Your system is Automatic Temp Control and is somewhat complex. Needs to be hooked up to a scanner to diagnosis system.

My 1998 A4 has 105,000 miles. My thermostat was stuck open - evidenced by the lack of heat in passenger cab and the constant cold temperature reading on engine coolant gauge. I just got the thermostat replaced and now have normal readings on the engine temperature gauge. However, I still do not have any heat available in the cab. Anti-freeze levels are OK. How can I determine if the problem is related to the heater control value, vacuum check value, blend door or other?

Follow the heater hose from the thermostat housing to the firewall and locate the return hose. Is the return hose cold? Is the supply hose warm, hot, or cold? If warm or hot follow it to a valve and feel the opposite side of temp. Your system may not be so simple but it should have a hot hose to the heater. If it is hot both in and out the damper door on a plenum is not opening.

Make sure as well that there is no air in the cooling system.

help i've bought a car with no heating, seller says he bought it also with no heater so have no history on how it went or why. its an audi a4 avant 1.9tdi estate 1998 (b5). a/c pump has gone but also have no heater, blows out cold air. Have bled the system for ages getting the air out, temp goes steadily to 90 most of time but occasionally drops suddenly. Top hose from radiator goes red hot all the time but bottom hose isnt as hot.i know the a/c pump has gone but i've checked thermostat; brand new, changed head gasket, timing belt, still nothing. vag-com results say too many errors (excessive comm errors) on channel 08; auto hvac. Altered density etc, but cannot get any fault codes for this code number however i try. Only found errors on channel 35; centr. locks.16 in total, 7 of these were unknown error codes.
any ideas?

With the engine running, hot, and the heat on high, feel both heater core hoses. Both should be hot. If only one is hot, try flushing the heater core. If both are hot, check the blend air door for operation.

both are hot, where is the blend air door? we've found loads of flaps and all seem in good condition

Slowly move the temperature control back and forth with the engine running and heater on. Watch for actuators and levers moving on the airbox under the dash.

everything ok there. tried flushing it through with a hose but it just blows the ends off. loads of shiny coppery bits in what came out but it did help a bit as the car now has a bit of heat coming out now. Read online it sounds like copperseal which was probably used as a quick fix gone wrong as I did the head gasket when I got it. trying some caustic soda and warm water in hose to try and blow it through rather than taking whole car apart again. will let you know if that finally fixes things for me.

Heater problem
1997 Audi A4 6 cyl All Wheel Drive Manual 130k miles
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There is very little heat coming out of the dash vents as well as the defrost vents..... I am not really sure of where to begin. The thermostat seems to be working and there seems to be coolant circulating through the system. The inlet and outlet tubes at the heater core seem to be hot. Any suggestions of where to begin...?What is the layout of the system? Is this care prone to a specific problem with the heater core, thermostat, air mix door?

i imagine coolant level is ok. coolant gauge on dash read normal? can you hear the blend door moving when switching from hot to cold?

You may end up having to pull the airbox out from under the dash and put in a new heater core. Let us know what happens. We'll be here.

[quote:7e015bdccd="mastertechtim"]i imagine coolant level is ok. coolant gauge on dash read normal? can you hear the blend door moving when switching from hot to cold?[/quote:7e015bdccd]

Coolant level normal, air blend door working, temp on gague moves.....
Any other Ideas? :?:
BTW I have made a donation under a diffrent email..

ok, update; done matrix, still no better on heater. radiator bottom hose stone cold. thinking blocked waterways on actual engine or maybe dodgy new thermostat?? help

i just looked to see if there were any bulletins for this problem and there are none. now if coolant level is up to temp and heater core is not plugged there could be a problem with the outside ambient temp sensor not raeding correctly causing blemd door to be inaccurate. this is about the only thing i can see.

I would suspect the thermostat or a clogged radiator. Drain the system into a catch basin/pan and see if water flows readily through it. Especially the radiator. Test the thermostat in a pan of water on the stove with a candy thermometer.

Have no heat, new heatercore, new waterpump and thermostat.

Hello –

To better assist please let me know if your model is just an A4 or an A4 Quattro. Also your engine size in liter.

Does the car reach operating temperature and hold at normal?

Are both heater hoses going into the firewall hot or one warm and one not?

It is getting col and would like to fix this fast as possible. I have owned this Audi for about 9 months I have all receipts from previous owner about 12k ago he had the heater core replaced, thermostat and timing done by an Audi dealer.. only warm air comes out the top vents. Both hoses going to the core get hot and i hear movent of vent flaps when i change the tem..

try removing hoses from heater core and blow through them to make sure its not full of debris. if that checks out ok then you will have to look real close at the blend door to make sure it is fully closing. what i do is lay under dash and move from hot to cold to find the door and make sure the actuator is moving all the way. there is usually a rod connected to a arm and there are adjustments on them, remove the rod and physically close the door and see if you get heat.

Well I did the easier of the two first.. Took down the glove box and under dash pad..changed from hot to cold the arm works great, smooth transition from open to closed... I am going to the local dealer to get some antifreeze...I think there is a bad mix in the car now "over the counter Autozone crap" I will take both lines from the heater core off and attach a hose to the one and see what flushes out. I tried bleeding it from there and did not see any kind of stream come out, it just dribbled out. I think we have found the problem.. Fingers crossed!

and congrats on being a Father!

thanks

Well i could use a little more help.. I tried taking both hoses off and attaching a garden hose to the inlet pipes going to the heater core..i put it one one then the other..it only flushed out some coolant nothing else...should I attach the garden hose to a hose on the car or the pipe inlet? Still no heat...thank you very much..

it flows out real fast with the garden hose?

this temp door motor works perfect, from cold to hot? i will keep looking and see what else i can find.

It flows out just as fast as the water from the hose...i will look at the flap again tomorrow.. I wasnt sure were to hook the hose up[ to is it the 2 plastic parts of the heater core assembly or the hoses going in and out of the motor? Thanks again.. one by one we will try all possible things

by flowing water through heater core itself confirms the heater core is not restricted. the inlet heater hose should be hotter than the outlet hose, if they are hot then you need to find the problem under dash

i have a september 1996 audi a4 1.9 tdi manual. mileage is 171000 my heater is blowing out cold air.i have checked thermostat and replaced. checked water pump its perfect because the strange thing is even i drive a long journey the coolant in the expansion bottle is just warm it never gets hot. both pipes going into the matrix are hot and the flaps to control the heat, which are manual are all working perfect. ive even flushed out the entire system. temp hand and car is normal and car is working otherwise perfect. is there anything else i need to do. ps on mild days i do have slight heat coming out but not enough

[quote:9d364239a1="decky"]I HAVE A SEPTEMBER 1996 AUDI A4 1.9 TDI manual .mileage is 171000 MY HEATER IS BLOWING OUT COLD AIR .I HAVE CHECKED THERMOTSTAT AND REPLACED .CHECKED WATER PUMP ITS PERFECT BECAUSE THE STRANGE THING IS EVEN I DRIVE A LONG JOURNEY THE COOLANT IN THE EXPANSION BOTTLE IS JUST WARM IT NEVER GETS HOT .BOTH PIPES GOING INTO THE MATRIX ARE HOT AND THE FLAPS TO CONTROL THE HEAT ,WHICH ARE MANUAL ARE ALL WORKING PERFECT .IVE EVEN FLUSHED OUT THE ENTIRE SYSTEM . TEMP HAND AND CAR IS NORMAL AND CAR IS WORKING OTHERWISE PERFECT .IS THERE ANYTHING ELSE I NEED TO DO.PS ON MILD DAYS I DO HAVE SLIGHT HEAT COMMING OUT BUT NOT ENOUGH[/quote:9d364239a1]

Hello !!
I think that the problem its the" valve " that opens the hot radiator water to the cabin heater core..

check that and be sure that its not "stuck" closed.

Also check the heater core (be sure that its not Plug by blowing compressed air in to the inlet)

let us Know!

Well at least we crossed the heater core off of the list.... I will take the arm off and try opening and closing manually... to be sure.. we are geting closer

[quote:31d7b8c784="fisherman"][quote:31d7b8c784="decky"]I HAVE A SEPTEMBER 1996 AUDI A4 1.9 TDI manual .mileage is 171000 MY HEATER IS BLOWING OUT COLD AIR .I HAVE CHECKED THERMOTSTAT AND REPLACED .CHECKED WATER PUMP ITS PERFECT BECAUSE THE STRANGE THING IS EVEN I DRIVE A LONG JOURNEY THE COOLANT IN THE EXPANSION BOTTLE IS JUST WARM IT NEVER GETS HOT .BOTH PIPES GOING INTO THE MATRIX ARE HOT AND THE FLAPS TO CONTROL THE HEAT ,WHICH ARE MANUAL ARE ALL WORKING PERFECT .IVE EVEN FLUSHED OUT THE ENTIRE SYSTEM . TEMP HAND AND CAR IS NORMAL AND CAR IS WORKING OTHERWISE PERFECT .IS THERE ANYTHING ELSE I NEED TO DO.PS ON MILD DAYS I DO HAVE SLIGHT HEAT COMMING OUT BUT NOT ENOUGH[/quote:31d7b8c784]

Hello !!
I think that the problem its the" valve " that opens the hot radiator water to the cabin heater core..

check that and be sure that its not "stuck" closed.

Also check the heater core (be sure that its not Plug by blowing compressed air in to the inlet)

let us Know![/quote:31d7b8c784]
reply by decky
sorry donot know where valve is .this audi has no air con have tried every thing nothing solves but if i knew where valve was i could check as i have a haynes manual for this car and it shows no valve either!

Just to be sure is the arm I am looking for located near the middle of the console under dash?

Well today all of a sudden the heater started to get more hot. not really hot but a good deal warmmer.. I took the arm off of the relay motor to see if I good get more heat but it did not get any warmmer... I am going to bleed the system a little more to see if that works. Can you figure out why? And is there anything more i can do to get more heat?

is it possible the thermostat is not getting hot enough? is engine temp in normal area?