Regarding hotspots:

Even if there are hotspots and the coolant deteriorates we need to consider
electrolysis through the deteriorating coolant. 
The next question is: where are the hotspots? 

Coating is a twosided option. If you do not have good heat transfer, where
does the heat go? Ideally heat should be transfered evenly but relatively
efficiently. Ceramic coating may also decrease electrolysis due to less
exposure of metal which is potentially positive. Another option to reduce
hotspots is to increase even flow. This can be done through polishing and
maybe also through some coating as well as through increase of the overall
flow (different waterpump?).

There was some talk about the Z-sticks recently, apart from having the
wrong thread do they work? Is there any longterm experience?

Bj�rn

Bj�rn Ratjen
Mill Bay, B.C.

1987 Vanagon est alia (self camperized)
1978 VW Bulli (self camperized)
1995 Passat TD Wagon (hers)
1970 VW Beetle (son's)