Audi A6 2.5 tdi help needed on a few issues!!

[dean warren]

Hi All I have a few problems with my A6 2.5 tdi with the AAT 5 cyl engine,

1 firstly the heater has stopped giving out heat, if you work her hard or keep revs above 3000 the heater gets luke warm providing you don't select any more than Blower speed 2 (no aircon).
I have back flushed the matrix, engine block and rad, they all appear fine, so I have changed the water pump, the one that came off was the original and date stamped 1994, and appeared fine after 292,000 miles , but still no heat, I have already changed the thermostat. Does this mean its defo the matrix?

2 when changing the water pump, I also fitted new belt and tensioner, I now have a fair oil leak from the front of the engine, I did remove the toothed sprocket to inspect the woodruff key for damage, it was sound, seal appeared fine before I re assembled it. Where could oil be coming from?

3. I have also renewed the injector nozzles, this has made a huge difference in power, however my tick over now is very rough, as if its going to stall I have used vag com to raise the tick over in a hope to cure this but it hasn't worked, iq is around 5 mg and timing is good on vagcom, any help on getting her ticking over sweet will be greatly appreciated.

[NH_USA]

1. Maybe a bubble in the cooling system!

2. You might have pinched the seal.

3. Is there an idle adjustment someplace? My 200QT had a screw stop near where the throttle cable terminated.