As I am sure you are all aware, the Volkswagen relies on not only air but also oil to keep the operating temperatures at an acceptable level. Once the oil temperature is to high, let's say over 230 degrees, the oil begins to lose its lubricating and cooling properties, thereby dramatically decreasing the life of the bearings, pistons, cylinders and other internal parts. Most high-performance guys run an aftermarket cooler to help with keeping oil temps down. There are a number of different ways to run coolers, from the stock "doghouse" to the Type IV oil cooler to the thermostatically controlled fan-powered units seem on a lot of the hi-po VWs today. This is all well and good, but how are you going to know if your cooler is doing its job and keeping the oil temps down? One way would be to install an oil temperature gauge and monitor it but that can be a bit pricey by the time you buy a quality gauge, sending unit and wire it all up.
Gene Berg Enterprises has come up with a nifty little dipstick gauge that automatically turns on the "idiot light" in you speedometer when the oil temperature reaches a certain pre-determined setting, between 220 and 225 degrees F.
There is a spring inside the dipstick that, when the oil temp gets too high, it rotates and grounds the shaft inside the dipstick, when it reaches the post that is connected the original oil pressure sending unit.
They have actually been around since the early '70s, and they are easy to install. If you can check your oil, and can crimp on a solderless electrical connection, then you can install the temperature dipstick with ease.
That's all there is to it, folks. It's much easier to just do it than it is to write about it. Some of you may want to run a separate light instead of using the stock "idiot light"; it can be used that was as well. There is a "shorty" version made that allows you to use it in an oil filter line, deep sump, or anywhere there is a 1/8-inch NPT thread is present with at least 1 inch behind it. Give Gene Berg a call; it may be the best gift you ever buy for your beloved VW.
SOURCE
GENE BERG ENTERPRISES
1725 North Lime Street
Orange, CA, 92865-4187
(714) 998-7500
Fax (714) 998-7528
Toll-free: (877) 568-BERG
This is the Gene Berg temperature dipstick. It takes all of five minutes to install, and could save your engine. The price is around $20. | 
Pull out your old, original dipstick (real hard, huh?) | 
Before we installed the Gene Berg dipstick, we marked the oil level on the new dipstick: the same level that was on the original. |
Make sure when you attach the wire to the grounding post, you aim the wire at the "9 o'clock" position, when you are at the rear of the engine. That way, if the temperatures are below freezing, the insulating wire will stop the grounding arm from turning counter-clockwise and contacting the back side of the grounding post. | | |
The other end of the wire, and the splitter, supplied in the kit, go to the stock oil pressure sending unit.