[TR] Push or pull

[Randall]

> Even if your gauge doesn't show a return, it has to help, surely.

Yes indeed, this should be part of normal maintenance on all Triumphs.  Many
later cars don't have a valve in that hole, but AFAIK all of them have the
hole.  Every 2 years (when the coolant should be changed anyway), remove the
plug or open the valve, and flush the system until clean water run freely
from the hole.  Even without the casting sand that Brian found, rust
particles and sediment tend to build up in the back of the block, and this
flushing helps reduce (tho not eliminate) the buildup.

Randall