Have  not heard of universal gauges where water temp and oil temp are
interchangeable. I would recommend against going  this "all in one" route
and
instead, installing one or more VDO gauges as you can afford them in the
following order of usefulness (as deemed useful by members of the list).
Oil temp (with sump plate sender <$40); oil pressure (with dual pressure
sender <$50) and then head temp (with sender <30). Prices are based on
what I paid. You could probably get them for less. I would also recommend
against going the mechanical route for the oil pressure, if for no other
reason that snaking a tube from front to rear could be a major headache
The response time would also be very slow. 

DC

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David Carment
School of International Affairs
Carleton University
Ottawa, Ontario
K1S 5B6
voice - (613) 788-2600-6662
fax - (613) 788-2889
Email address: dcarment@ccs.carleton.ca
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