audi a4 1997 heater poor

No, you are still in thermostat world.

Has all the servicing been done?

Possibles are : Not hot enough coolant (short journey, failed thermostat), blocked heater matrix, faulty valve or flap mechanism, air lock, blocked pollen filter,

mrcheerful

any idea where the thermostat is located? i guess its the most likely cause

If the heater matrix is blocked is it a big job to clear it?

The heater matrix needs changing as it is blocked up with sludge from the engine. The likely causes are corrosion in the engine caused by not having the correct amount of antifreeze (inc rust inhibitor) in over the years. Or one previous owner just filling up with water and neglecting the car. Then it is often made worse when people sell a car after fixing it with RADWELD to hide leaks. It makes all the sludge in the matrix block it and turn solid. You can try to flush it out with a fairly high pressure hose. The water will come out brown for a while. Often it doesn't work too well. So if you can do an impression of a vet and get your hands up behind the dashboard to change the matrix you will be OK. People will give lots of incorrect info stating it is your fan, resistors, switches, engine thermostat etc. It is a common problem I have seen on many cars. Average cost of replacement in a main dealer is terrifying. Independant garages charge around £130. The actual matrix is around £45 max. Good luck. Don't start messing with the engine thermostat as this is not inline with the heater matrix. It's a common mistake people make in thinking it is. They don't understand how the engine, thermostat and matrix are connected up. You can see for yourself if you have a look under the bonnet, look where the pipe comes from the engine to the matrix in relation to where the radiator and thermostat is.

Rubbish, you don't understand how the system works, if the coolant is below temperature due to a faulty thermostat then the heater will be substandard. On a vehicle as recent as this then the first check is what temperature is the engine reaching? and if low then change the thermostat.

The thermostat can and should PREVENT coolant reaching the radiator (and cooling), if the thermostat is stuck open then the coolant cools more than it should and so only lukewarm water reaches the heater matrix.

If it is the heater matrix then replacement can reach 500 quid in a dealers.

IIRC most Audi have a plastic lump containing the thermostat, fairly easy to reach.

Mrcheerful

Listen to Mr Cheerful - look at your temperature gauge - if it shows lower than it used to (i.e. when the heater was working better), then it's almost certainly the thermostat, if it shows normal, then it's likely to be a blockage/sludging or a failed valve. Just had similar problem with my Zafira, temp gauge showing much lower than normal, particularly when running at 30-40 mph, and slow to warm up. £9 for a thermostat, fitted it myself. Went from lukewarm heating to roasting - lovely. Old stat looked absolutely immaculate, and was completely closed when I took it out, so it must have been opening early rather than totally failed.

Biggles

You would do to if you were washed constantly @ 80~95deg C ;-)

are there any photographs online anywhere showing the location of a stat on the audi a4

Haynes will tell you. Failing that it's not hard to find. It will be in a housing, so follow the pipes from the radiator back. Some will disappear straight into the head/block, and others will connect to a box with bolts.

Follow the top radiator hose.