Specializing in low tech effective tricks...
Here's a nice little trick..loosen the screw on top of the radiator ..
so it leaks a little.
Drive around until well warmed up.
If you temp gauge does not come up to about the middle it's not running
up to temp.
If it never gets above say 1/4 on the gauge in not-demanding conditions,
it's running too cool. Get a new german t-stat in it.

anyway ..drive around a while  a good 20 minutes. ...air and a little
coolant should fizz out of there.
Then tighten the screw.

also ..this works just great, as long as things are basically ok...no
leaks mainly......... anywhere.
Each cool-down cycle, if there is much of an air space in the Pressure
Bottle, top it up.

it can take 4 to 6 warm up/cool-down cycles for there to not be an air
space there. Like an hour or more after running.
It may want to always have some air space... if it wants to be 1/2
inchthere, that's ok.

they'll bleed that way fairly well. Have both heaters on half way or
so.  Expect that the rear heater core leaks a little ..very common , if
they have not been replaced or blockedoff/bypassed. Valve on the side of
the rear heater should always be on some so fresh coolant circulates
through there.
If there is always an significant ( like 2 inches ) air space a the top
of the Pressure Bottle after good every cool-down ..say more than 10
times in a row ..something is wrong somewhere.

scott

On 9/6/2013 9:16 PM, David M wrote:
> Continued my coolant top-up operation. Refilled tank again and brought engine up to full temperature. Gauge stayed in middle, radiator fan came on high-speed. Coolant tank overflowed so I stopped engine and screwed top back on tank and reconnected hose. Ran engine again and coolant went down a little more. Still NO coolant came out of thermostat bleed valve.
>
> David (1987 Wolfsburg)
>
>
>
> ________________________________
>