Hi

I have a 97 Audi A4
Picked up in Atlanta, so the heat has rarely if ever been required.
Trouble is I live in Michigan and need the heater to work.
Diagnosis as follows:
- New pump
- New Thermostat
- Bled system
- New coolant

Start car and leave at idle - no heat
Rev up to 3,000 to 4,000 rpm - lots of heat
Heater hoses at firewall hot when car idles.

Thought it might be heat damper stuck or valve that controls damper door.
However if there is heat at high rpm's, this might not be it unless the high rpm's trigger something under the dash too.

Is the damper valve vacuum or electric?

or

Does someone think it something still with the coolant system I have not touched yet?

Oh help before I freeze to death here!

Doug

 

DOES THE FAN COME ON WHEN YOU TURN IT UP?
NO FAN = NO HEAT
SAME THING ON MY OLDER 100
REPLACED FAN AND NOW THE HEAT CRANKS............

 

Have had several people contact me asking what the resolution was.
After dealing with several Audi specialist's who knew bugger all and took my money. (Only one of them was honest enough to admit it and reduced his hourly rate).
The other noob told me they were as talented as the regular Audi technicans and were entitled to the same hourly rate. Pfffft - IdiotEuropean Car Specialist located in Pontiac.

The problem is that in the older Audi's the flaking grit collects in the heater core and flow of the system is not strong enough to flush it out.

I picked up two radiator hose's and put garden hose connections on one end.
Disconnect the heater hose connections at the firewall where they go to the heater core.
Keep the disconnected hoses elevated, DO NOT START THE CAR WITH THEM DISCONNECTED!!!
Put my two radiator hose's on the heater core connections.
Hook my garden hose to the sink connection and flush with hot water to warm up the heater core.
Pour in undiluted Prestone Coolant Rust Treatment and let sit for 5 minutes.
Flush out with hot water.
Repeat and flush in opposite direction.
Pour in undiluted Prestone Coolant Treatment and let sit for 5 minutes.
Flush out with hot water
Repeat and flush in opposite direction.

It does not take much grit in the heater core to clog it up or reduce it.

Put the coolant system hoses back on.

Remember you have to bleed the system.

There are two bleed points.

One is behind the engine on the right side way down and has a stupid Audi design bleed plug. German engineering sometimes stinks.
If you have not doneanything to pull air into the system you might not have to do this step. If you did, enjoy the frustration.

Find the bleed valve in the pipe run behind the engine.
If it is a older Audi, it is probably seized.
Ripped mine out, took it to hardware store.
Found a metric bolt with the same thread and length.
Tapped sideways through bolt and up inside the thread area. Clean, clean, metal shavings real bad news for coolant system.
Got a high temp gasket to fit.
Installed.
Now I can reach down with my metric socket set and bleed very easily thank you very much.
The engine does not have to be running, this is a high point in the lower coolant system and any air will bubble out.

The second bleed point is on the passenger side hose connection into the firewall.
Disconnect you coolant resevoir, lift it as high as possible. I hold mine up with a bungee cord, it has to be higher than the heater core and have enough coolant in it.
With engine idling, back off hose till bleed hole in hose starts to bubble out.
Do not rev engine as it creates a vacuum and will suck the air into the system.
When bubbling stops or is very little, push hose back on.

I do this every September as replacing the heater core only will not solve the problem as the flaking grit will still continue to build up from the coolant flow system. Parts of the coolant flow system are metaland they are breaking down. The heater runs great all winter, then come summer, it plugs up again. After doing this for so many years, have it down pat and can finish it in a hour.

Love the car, just one of the quirks of owning a older Audi.

Doug

 

Problem is yu have air in ur cooling system. The reason why u still get the problem inspite of bleeding is, you have a leak in the cooling system. Try pressure testing. It shld tell u weather the leak is there or not. It need not be big leak and u will not find the coolant level going down, but will be enough for the sir to get in and cause air pockets. At higher RPMS, the coolant flows at high pressure and disssolves the pockets, so u will see heat coming out. Possible issues cld be gaskets (valve cover, head gaskets (if u r v unlucky)) or some leak at the o-ring etc.

 

^^ He solved the problem, and it wasnt air...

 

My 04 Mini non-S has no heat. It has NAV, thus no temp gauge, so I have no idea how hot the car is running, but I do know the radiator fan comes on during extended idle, so Im guessing the t-stat is not stuck open.
First the coolant was low in the expansion tank so I filled the radiator and tank and was squeezing the upper radiator elbow hose to feel for flow when it sprung a leak in my hand. Seems it had been wearing on a corner of the alternator. I then replaced it at a ridiculous dealer cost of 45 and filled up again. Im guessing it got some air in the system when I topped off the radiator, if it didn’t already have some in it. I have tried bleeding the system with the two bleeder screws one just behind the elbow hose I replaced and one under and left of the battery on the hoses to the heater core, but have not been able to get the heat back. Fluid always come out, but it accompanied by bubbling – not sure if that is normal. Someone told me I should drop the lower radiator hose, drain all the coolant and start over with a re-fill. So what is the proper procedure for getting air out of the system? Is there a sequence for bleeding? engine off/on? heat off/on? I don’t want to drive it and blow the head gasket

 

heater core is more then likely the issue, the cores are cheap but install is a real pita, you have to remove the entire dash.

 

Your Mini.....? Cooper........? Non-S.......?

This is an Audi Site...... Not BMW

i'd run the car for about an hour with the coolant cap off.....

Those bleeding screws are just removing air from that part of the motor... aslong as you have coolant in the system, you won't blow a head gasket...

 

the heater core like to clog, take off both ends of the heater core hoses and run clr into it let it sit for awhile and the flush the heater core a bunch of **** will come out. and ur heat will be better, it may take a few times.