(See Gene Berg's negative comments regarding gauges below.)
Dave installed an oil temperature gauge in his Bug, using an oil relief plug type sender. See the procedure for this installation.
Temperature Sensors -
There are two types of oil temperature sensors -
Wiring -
“Jerome” shows the following wiring arrangement -

You may find that the wiring arrangement shown in the (VDO) gauge installation instructions is quite different.
Wiring Notes -
Study the manufacturer’s instructions carefully - they are never very clear to me.
"Speedy" Jim wrote regarding the routing of the sender wire -
Lift the rear seat and locate the rearmost part of the pan where the sheet metal slopes upward. Drill a small hole there to route the sender wire into the under-rear-seat area. Be sure to seal the hole with caulking after running the wire through it. From that point, route the wire forward along the tunnel, under the carpet.
Rob added -
It would be a good idea to make some kind of little support for the sender wire so that it doesn't droop and doesn’t pull on the sender itself.
If you don't want to disturb the glued carpet, you could possibly run the wire under the car all the way to the front, and then drill a hole there to get it into the luggage area. If your car has the small slot in the bodywork just under and to the left of the fuel tank for a drain tube (I can't remember if the Supers have such a drain tube), then you could run the wire through that.
Gene Berg says, "Most gauges are "horrible." He continues -
I hear daily of engines being destroyed by people relying on gauges. I have run hundreds of accuracy tests on practically every inexpensive aftermarket gauge under $125 offered. Practically all read low in the 212 to 260 degree range by 40 to 50 degrees on oil temperature... Oil temperature gauge readings would be 212 to 220 degrees on the gauge when the true test temperature was 240 to 260 degrees... I swapped gauges with senders and got different readings. I found nothing in that price range I would wish on my worst enemy. Not one I tested could ever be properly calibrated or relied on in any way for any valid information or even as a comparison from day to day on the air cooled VW.
Warning: If you want gauges as a decoration fine, but never rely on them. After all, if they provided reliable information I would be selling them to make a profit just like our competition.
Disclaimer stuff: Rob and Dave have prepared this information from their own experiences. We have not assumed any specialised mechanical knowledge, but we DO assume that anyone using this information has at least some basic mechanical ability.
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Last revised 24 May 2004.