88 80 Quattro. Replaced the engine to heater coolant hose w/ a new one that has a fresh, unbroken bleeder valve.

I noticed after the first drain/water fill that the car was blowing a little white smoke/steam out of the exhaust once I parked it for the day (as the bleeder screw wasn't sealing).

Flushed it again today, filled with water. As I was warming up the engine to let the thermostat open, I noticed that the white smoke was more intense than before. Now, as the coolant temp gauge moved up a few ticks above C and the heat was blowing plenty warm, the exhaust had a fair amount of white steam/smoke, especially if I held throttle at 2000-2300 RPM.

(Also, I may be smoking something, but I think the oil level went up a smidge again (4mm or so above full mark now), whereas I think it was about 3mm before. But that was with a cold engine.)

So now the coolant is 25% old stuff (12.5% antifreeze, presumably) and 75% fresh water. Or maybe 20/80. Each drain was about 4.5L of fluid.

Do you think the previous owner has used something like a Leak Stop product? Is this a blown headgasket?

Should I pour some kind of a leak stop in when I put actual antifreeze in today? (I was going to put in 4L Dexcool). I assume that's gotta be better than burning antifreeze.

Or is this all going to go away when I put some actual antifreeze in the system?

(Also, how screwed am I? Taking this to a real Audi mechanic tomorrow, but it's an hour's drive away).

When I drained for the 2nd time, this afternoon, I noticed chunks of metal/rusty stuff on the drain pan:

<a href="http://www.flickr.com/photos/uksi/5146325207/" title="Rusty stuff after 2nd coolant drain by ilp, on Flickr"><img src="http://farm5.static.flickr.com/4046/5146325207_476a047b58_z.jpg" width="478" height="640" alt="Rusty stuff after 2nd coolant drain" /></a>

Original fluid was near black:

<a href="http://www.flickr.com/photos/uksi/5146925012/" title="Original coolant drained by ilp, on Flickr"><img src="http://farm2.static.flickr.com/1152/5146925012_9df60183bf_z.jpg" width="478" height="640" alt="Original coolant drained" /></a>

(I wonder whether that was partially due to mixing of coolant types?)

2nd flush today was brown, which is approx 50% water, 50% old stuff:

<a href="http://www.flickr.com/photos/uksi/5146926546/" title="Fluid after 2nd coolant drain by ilp, on Flickr"><img src="http://farm5.static.flickr.com/4062/5146926546_8feea06c43_z.jpg" width="478" height="640" alt="Fluid after 2nd coolant drain" /></a>

 

Definitely think that's Barr's Stop-Leak flaking off your hoses, radiator innards. The brown hue of the drained coolant says Stop-Leak, too.

If you're running your engine up to 3000 RPM with water leaking in through the head gasket, your oil would be getting white foam in it. The white foam would then stick to the dip stick.

Can't say for sure though. Looks like the previous owner might have had minor issues. Anything serious would have shown up for you before now IMO.

 

Didn't see any white foam on the dip stick. So it must just be leaking into the combustion chamber then.

Sounds like I should just put a can of Bar's Leaks Head Gasket Fix or something similar and keep cruising.

 

that or it will plug your T-stat.

 

Update: So after I ran it for an hour, with actual coolant in there, it stopped smoking by the time I was done with an hour's drive.

So maybe the water was getting hot and evaporating, but once the coolant got in there and cooled things down, then there was no more evaporation.