Tons of oil temp gauge info Options

[McMark]

I had to do some research on the oil temp sender setup as well as researching how to integrate an aftermarket VDO setup. I found that our info here was sorely lacking. So I decided to put everything I found in one place.

Stock System:

Sender
Markings on the hex portion of the sender itself.
1. VDO - manufacturer
2. 6-24v - operating voltage
3. 200*C - upper temp limit, this sender feeds a gauge that peaks at 400*
4. 801/7/2 - ?????
5. Made in Germany - location of production
6. 12.72 - date of production (changes, Dec 1972 in this case)

Threads are 14mm x 1.5. This has been improperly quoted in the past. I just measured it myself.

These senders operate in a range of 3000 to 1000 ohms (pretty sure on this, my sample measures 2500 at room temp).


Mount Plate
The stock oil temp sensor mount is commonly referred to as the Taco Plate. This name originated from its tendency to bend in the middle when overtightened, like a taco. The stock system includes a sender cover plate which protects the components, and (IMHO) is mainly there to protect the wire from being unplugged accidentally. The mount plate itself uses a large red o-ring to seal to the engine case. The sender cover uses a circular paper gasket.

The plate/cover mounting bolts at 6mm x 1.0 and are 10mm long. The bolts are sealed by using two copper crush gaskets.


Connecting Wire
Wire is 18g Green jacket with a black stripe. 40" overall length, female spade connectors on both ends. Green wire is available at most auto parts stores and a Sharpie can be used to make the black stripe. The wire is routed through a rubber grommet in the sender cover plate

The wire is attached to the motor at three points by sheet metal brackets which are crimped onto the wire.
1. The first connector is attached to the sender cover plate. From here the wire routes above the motor mounts to #2.
2. The second connector attaches to the lower mount bolt for the oil filter console.
3. The third connector attaches to the lower oil cooler to fan housing bolt.

#--3"---|-------------11"--------------|-------8"--------|---------------15"----------#



Gauge
The stock center console gauge came in two setups. They do not have any numeric indication of oil temperature, but rather have a red section at the top of the range which indicates when the motor oil is getting too hot. The red section on the 'early' gauges is larger than on the 'later' gauges. AFAIK, the readout of both gauges is exactly the same, and Porsche redesigned the gauge because owners were nervous/cautious/concerned about the normal operating temperature was 'too close' to the red on the early gauges. These gauges have a 60mm mounting diameter.

An uncommon third gauge replaced the blinking brake warning light in the left hand combo gauge. This sender came in 'silver button' early type and the late 'blank' style. On these gauges the large red warning light was moved to a small red light in the center of the gauge.

VDO Components

Gauge
Upgrading to a VDO oil temp gauge is beneficial because of the numeric representation of oil temp. There are quite a few options for these gauges, but most commonly used are the Cockpit versions which look quite similar to the stock center console gauges. When using these gauges in a stock center console, some modification has to be made to account for the smaller OD of the VDO gauge, since these gauges feature a 52mm mounting diameter. I forget what size, but a section of black ABS pipe can be used to take up the difference perfectly.


Sender
VDO senders use a 150*C/300*F standard peak temp and are therefore not interchangeable with stock senders. VDO senders operate in a range of 10 - 180 ohms. VDO makes a sender that is compatible with the stock mounting plate, part number: 323-055D.



There is more information out there, but that's all I have at this time. If you've got info to add, please do.

[McMark]

Picked up the latest issue of VolksWorld (Feb 2011) and they did a side-by-side comparison of a few different oil temp gauge & senders. You can order the mag for all the details, but the conclusion is that nothing was less accurate than the VDO. Best accuracy was from a Stack ST3310.

IIRC, the margin of error on the VDO was 20+ degrees.