[Vwdiesel] Oil in coolant, headgasket etc....

[Sandy Cameron]

At 11:41 AM 15/11/04 +0200, you wrote:

Had the engine running
>for about an hour in all with the hose bypass, didn't see any oil coming
>from any where, (so I guess it's OK) took it off in the end.

Thats a GOOD sign,,,,

>The temp. guage and warning light max out 'cos there's no coolant in the
>tank...

The warning light should come on, but I would not expect the temp gauge to
max, as I thought the sensor was in the front outlet from the head.

>Flushed the system out with a litre of alchol and quarter of a bottle of
>floor cleaner. There was loads of black crap in there... it feels like
>grease, kinda sticky not "oily", really difficult to get off your hands. No
>smell. 

Now this I can identify with this... Last winter I was having trouble with
over heating in the 87 jetta, all symptoms pointed to a plugged rad.
Pulled it out and took into the laundry room and started to flush it in the
big sink.

All kinds of black slime came out in blobs. Not oil based.

Concluded (Mia culpa) that my habit of "recycling" old antifreeze over the
years , drained from other cars, etc, was a bad idea. I also discovered that
old antifreeze (you can tell by the smell, it's acrid acid smell) turns to
slime as it breaks down, or little critters nosh on it and poop the black
slime.. Anyway, cleaned the whole system out and got some of the "good
stuff" orange colored and mixed half/half with demineralized water. That's
all I use now. 
And I never re-use antifreeze.

My overheating problem disappeared immediately, and I can pound the s*** out
of it, hauling trailers, etc, and the gauge never budges from the center.
>
>Put a clear section in the 1" hose that runs back to the expansion tank.
>(branches off the head to rad?? hose that split) At idle I don't get any air
>bubbles.  Accelerating gradually there are no bubbles until I drop the revs
>off, then there is a bust of "foamy" bubbles.  Same happens if I blip the
>throttle, bubbles come on the release. With the cap off, and my hand on, the
>expansion tank, there is loads of "suck" during acceleration and higher

Now that's Odd, may be related to local boiling in corners of the head where
temp is higher than coolant boiling point, esp at atmospheric pressure.
I think the psychology of the volks cooling system is to raise the boiling
point significantly by running the system at some pressure, anyway, it seems
a bad thing to run with the lid off, as it will boil in the head, and reduce
the cooling action.

Sandy