Do you want the information or are you more interested in a gnarly-looking set of gauges for cosmetic purposes?
A VDI oil-temperature gauge (with the required sensor) is available for about $90 (
Volkswagen New Beetle 1.8T > Interior > Gauges > Oil Temperature > ES#9860 52mm Oil Temp Gauge - 300F - GAU003). A simple DIN-size Gauge Holder for the New Beetle runs about $25 (for one to three gauges,
Volkswagen New Beetle 1.8T > Interior > Gauges > Gauge Panels > ES#1174 Din Panel Gauge Holder, 1-Hole - MK4DP 1H).
If you want the information without the need to cut into the wiring harness, there's the ScanGauge II (
ScanGaugeII : Linear Logic - Home of the ScanGauge), which includes more than 15 built-in digital gauges, 5 sets of trip data and an easy-to-use ScanTool that shows both set and pending trouble codes. The ScanGauge II just plugs-in to the diagnostic port at the lower left-hand side of the dashboard. A number of us have used this tool for several years; very cool! Amazon has the ScanGauge II for $94.95.
If you've got an iPhone, iPod Touch or iPad, a very slick alternative is the GoPoint Technology BT1 (
BT1 - Bluetooth Diagnostics with Android, iPhone and Windows Mobile 7 | GoPoint), which just plugs-in to the diagnostic port, then gets BlueTooth-paired with your device and provides "live" gauges for a broad range of ECU readouts (including oil-temperature), can scan/reset diagnostic codes and serve as a versatile trip-computer. GoPoint currently has it on-sale for $59.99 (versus list-price of $119.99) and all of the apps are free (instead of $5.99/each). I've switched-over to the GoPoint BT1 from my ScanGauge II...
Good luck!
