2005 Audi A4 Heater Not Working Properly

Tiny
LEAHB
  • MEMBER
  • 2005 AUDI A4
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 18,000 MILES
My heater gets hot during high RPM and cools off during idle. I had the thermostat changed last week and it did not correct the problem. Can you suggest what needs to be done?
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Wednesday, December 3rd, 2008 AT 8:33 AM

4 Replies

Tiny
IMPALASS
  • EXPERT
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?

Next, if it is drivable, please go to Auto Zone (AZ) or O'Reilly's (OR) and for FREE they can pull the codes to the car. Most important: Once they check your codes, if they find something and you don't get it fixed and need to get back with us, please make sure you tell us exactly what the code was, number and all. Example, if the code was E0568 O2 Sensor bad. Then make sure you give us all of that. While there for FREE also they can bring their tester out and check your battery, alternator and starter.

Last you only have 18,000 miles on your vehicle?

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

Please answer/do the above and get back with me and let's see if we can get you some steady heat.
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Thursday, December 4th, 2008 AT 7:08 AM
Tiny
LEAHB
  • MEMBER
*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.
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Thursday, December 4th, 2008 AT 8:39 AM
Tiny
IMPALASS
  • EXPERT
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?


http://www.2carpros.com/forum/automotive_pictures/248015_125787940_1.jpg



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.


http://www.2carpros.com/forum/automotive_pictures/248015_1_100.jpg



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


http://www.2carpros.com/forum/automotive_pictures/248015_2_65.jpg



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.


http://www.2carpros.com/forum/automotive_pictures/248015_3_48.jpg



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.


http://www.2carpros.com/forum/automotive_pictures/248015_4_28.jpg



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.


http://www.2carpros.com/forum/automotive_pictures/248015_Picture2_21.jpg

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Thursday, December 4th, 2008 AT 7:10 PM
Tiny
LVMORA
  • MEMBER
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
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Sunday, December 13th, 2015 AT 12:26 PM

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