For the lights of me, I cannot locate the engine block drain plug (or petcock, or whatever is called).
I kept looking at the instructions, and I kept looking under the car... no way to find a "semi-flush, recessed Allen fastener".

Is there any other way to flush out all the coolant without removing the drain plug I could not find?
Would the old-style of running the engine for a while with a water hose in the expansion tank would clean up all the ducts, or would I have to unhook some other top coolant hose (by the heater core) and run water through that one?

Thanks.

 

well, nevermind.
If I still don't find it (although now I have a hunch based on EBahn's unintelligible and unexplained illustration, and the possible locations that resemble the area in question), I'll just run water through the whole thing a couple of times with the engine on.

Thanks for all the help...

 

I'd use the plug at the bottom of the radiator and flush - flush - flush making sure it heats up enough each time to circulate water thru the heater core.

PS The use of toilet paper before flushing is not recomended when working on an Audi. It is better if you use kids alcohol wipes.They will help you get use to the pain-in-the-butt vehicle

 

Thanks much, Fred.
Actually I already went through 2 cycles. Everytime I let it idle for about 10 minutes, and the drained or flushed water comes out hot on the bottom of the radiator.
However, I noticed that with the heater on high, and temp dial half way, it doesn't blow hot air, so definitely I needed a thermostat change.
In these conditions, I would assume that the water doesn't circulate all the way to the heater core anymore. Any chance to have old coolant "trapped" in the heater core that remains unflashed?

I apreciate immensely your chiming in.


P.S. By the way, I found the engine block drain plug. I couldn't see it b/c of the belly pan support, which fastens right on the transversal beam and was screening the view.
It has an 8 mm Allen Ball head. I don't have the right socket bit for it (bought a 10 mm last night. Couldn't remove it with a regullar wrench so I gave up on it.