Ignition retard knock sensor.

[Bruce Plecan]

| The way I thought it worked was that the oil was over heated by the turbo.
| A water cooled cartridge cools the cartridge and prevents excessive heat
| from transferring to the oil.  Is this not true or is it just the case
| that it reduces the heat transfer to the oil, but not necessarilly enough
| to not worry about it?

It might reduce it slightly.  I've even heard some discussion, that the only
time a water cooled center section is really effective is during engine
shutdown,and it allows for some coolant circulation like the ol MG's and the
thermal dyne cooling systems.

| > Buzz words turbo overheating, you can percolate oil til it easily losses
it
| > ability to lubricate bearings!.

| Would excessively dirty oil after relatively few miles (about 1400) be an
| indication of overheating the oil?  I attributed the dirtyness to
excessive
| blowby from running boost continuously for such a long period of time on a
| high mileage engine (it's got about 100,000 on the clock).  It only
happened
| during the trip.  Prior oil changes (only one at about 2600 miles) with
the
| turbo looked normal.

Part of what oil "breaks down" into is carbon.  Also, as a byproduct of
combustion various acids are formed which react with the oil.

| > | Perhaps though, now that I know I will be running extended boost when
| > | loaded down that I should get one to know what's going on and install
| > | an oil cooler if necessary?

| > Measure the temp., and see where you are.  Get a temp., and call Earls'
or
| > someone to get a rough idea of what you need.  Why bother putting one on
if
| > it's not sized right.
grumpy

| Good point.
| --Dan