If the engine is cold, and your parts are ready for install
you shouldn't lose much coolant.

Not to get OT, but it's easy to inspect the green O2 wire at engine harness.
Images: https://picasaweb.google.com/musomuso/New1988Westy#5748856721901671282

Wires, contacts to the coolant temp sensor can get fouled up over time.

On 1/26/15, Stuart MacMillan <stuartmacm@gmail.com> wrote:

> Still chasing bugs in my son's '87, and I'm going to replace it and the O2
> sensor.  It's got erratic high idle, stumbling when cold, and I think it's
> running rich when warmed up.
>
>
>
> Just wondering if there is a way to minimize coolant loss.
>
>
>
> There are a lot of pipes into the T-stat housing, and I can't clamp them
> all
> off.  And, does the O-ring tend to stay in the bore and need to be hooked
> out, or will it come out with the old sender? I'm going to replace it.
>
>

--
Neil n

Blog: Vanagons, Westfalia, general <http://tubaneil.blogspot.ca>

1988 Westy Images <https://picasaweb.google.com/musomuso/New1988Westy>

1981 Westfalia "Jaco" Images, technical <http://tubaneil.googlepages.com/>

Vanagon-Bus VAG Gas Engine Swap Group <http://tinyurl.com/khalbay>