I have finally finished my project mounting an oil temperature gauge on my 996 C2 2002. I am very pleased and I think it got even better than I expected.

The most complicated part was to find a good spot for the oil temperature sender on the engine. I decided to use the hole on the left hand side cylinder head that is the same hole as where the oil pressure sender is located on the right hand side. That hole is just plugged with a blind plug. Since I had a little accident with my old engine a couple of years ago I have a spare cylinder head laying around so I could test fit everything on that head.

At the bottom of the oil pressure hole on the head there is an oil channel, and I wanted to make sure not to block that channel. That means that the sender can be 10 mm long. The tread is an M14x1.5 and first I bought a sender for that tread. That sender is however a bit longer than 10 mm and quite thick as well. The solution was to buy an M10x1.0 sender instead and then put that sender in an M10x1.0 to M14x1.5 converter. Unfortunately I had to drill out that converter about 1 mm to get the temperature sender to fit. I also cut it of a couple of millimeters to make sure the oil reaches the sender as much as possible.

The sender looks like this



Then I routed the signal wire from the sender into the back seat (there is a rubber plug just beneath the DME), and then on the right hand side under the panel and carpet under the back seat and then up through the center console and all the way to the dashboard.

I wanted to keep the storage compartment so I decided to cut a hole in the storage compartment to accommodate the gauge. It looks like this:




With the mounted gauge it looks like this




And finally in the car it looks like this




As can be seen on the pictures above, I cut the "rubber carpet" in the storage compartment to cover the gauge installation. I still have some minor polishing of the storage compartment to do, but this project is pretty much done.

I am a bit surprised that nobody sells this as a kit since I have seen several people here on Rennlist asking for an oil temperature gauge for their 996. But now I have made my car a bit more track friendly at least.

 

Hope it forever tells you good things.

 

Robo, nice work man! If you happen to have any more pictures of the engine and attachment please post! I still have a few small projects left and this is one of them that I need to address in June.

 

I don't know exactly what kind of pictures you need but here is one of my installation.

Below is a picture of the sender mounted on the cylinder head. The sender is pretty much in the middle of the picture. You don't really have to remove any hoses to get access to the hole for the sender. I just used a zip tie to keep some hoses out of the way while I fitted the sender. I routed the cable behind the alternator and throttle body. Some time when I do some more work on the engine I am going to re-route the cable to follow the big cable harness over the engine, but for now it works fine. I put a connector for the signal cable next to the "plus-cable" connected to the engine (on the right hand side of the engine). This is to make sure that the entire engine can be removed without any issues. If somebody else than me removes the engine I don't want them to forget this cable. I then used zip ties along the "plus cable" to route the signal cable all the way to the rubber cap beneath the DME in the back seat.

 

Good stuff!
Thanks for your description. Just to make sure I understood correctly: the M14x1.5 thread is there already beneath the plug?

 

Yes, the M14x1.5 is the thread in the cylinder head.

 

FWIW : this is a great position to get an easy to access oil temp, BUT , be aware that this is AFTER the oil cooler and BEFORE the oil has done any real work of extracting heat/lubricating from the engine.

The reading here is valuable but will be LOWER than what will be read in the sump, AFTER the oil has done work/extracted heat from the main and rod bearings.

I would expect the temp here to be 20 degrees lower than what would be read in the sump and will show the effectiveness of the oil cooler..

 

hmmm, interesting. I have a durametric that reads the temperature from the sump. I am going to check my gauge against the durametric…

 

Maybe someone can explain this in non electrical engineering terms to us uneducated folks. If the durametric can measure the oil temp from the sump by plugging into the ecu, is their a tool that can be used to plug into the ecu that can be connected to a digital gauge that can read the oil temp without having to worry about messing with plugs and connectors on the engine. Simple plug and play. Why go thru all the fabrication trouble? What am I missing?

 

Because getting the information off the dme and onto a simple digital read out takes an electrical engineering degree. There is a thread out there that im sure someome will bump but u have to build a cuircut board and wire up a bunch of things then find a nice spot for the read out. Not sure if a cheap obd2 scanner would work but u would have to reboot it everytime u turned the key and there is no way u could read the data while driving.

 

YOU THE MAN! Thanks for the simple explanation. Now I get why the circuit board conversation keeps popping up when we are discussing a DME oil temp tool.

To your point, at this time, it soesnt seem that there is a "plug and play" product that exists which is simple to the point that you plug it into the DME and it has the circuit board already configured that on the other end is a gauge that you velcro somewhere on your dash or steering column for track use to monitor oil temp?

If anyone knows of one please let me know. Seems like a no brainer for a product. Especially for guys like me that would rather get a root canal than figure out how to configure electronics or various sensors with connectors and wires on the car.

 

@GC996 I’m working on a solution very close to what you’ve described. It’s in the “bench test” phase now, but I plan to install it in my car in the next few days.
Basic description is like this: I designed a pcb and installed an arduino, voltage regulator. The arduino contains an imbedded code (written by me) that reads the temp signal from the DME and outputs a reading to an OLED display. There’s three wires on the input side (+12v, ground, and signal). Only one wire needs to be spliced into the DME oil temp signal. This is a long wire from behind the seats up to a convenient place where +12v and a ground are available. I plan to use the outdated phone connector behind the center stack and locate the pcb in that area. The location of the pcb is considered a permanent location that’s out of sight.
There’s four wires that run from the pcb to the display. You can see from the pics below, I plan to mount it in the batwing of the stack initially, but may not be the final location. In reality, the display could be placed anywhere based on driver preference. A connector can be incorporated so it’s removable, but all wiring will remain in place.
Everyone likes to see pics:
Heres the basic set-up:


Pcb with arduino and voltage regulator to the left, OLED display on the right

I created two versions of the same code. This one just shows the temp

This one adds some text above. Not sure which version I like better.

A connector on the back of the display makes it removable, bit all wiring remains in place
​​​​​​​

 

Coop, if you can make it simple for knuckleheads like me to plug and play, I think you will sell alot of these. Many of us are looking for easy way to monitor temps on the track. The key is to be able to velcro a small dispay in sight on the steering column or attach to windshield. Looking forward to your progress!

Same can be said for Robo's which may be a permanent gauge using the LN spinoff for the oil temp source.

Again, the key is small display within eyesight. When you are on the track, it's not practical to move your eyes anywhere but directly in front of you.

Appreciate what you guys are doing. We have needed this for 20 years!

someday, someone will come out with an aftermarket redesigned dash that allows for a few more gauges within eyesight. Until then, we gotta work with what we have. Fingers crossed on the next wave of 996 restomods. As much as I love the look of a few more gauges at or below radio level, they just aren't practical.

 

I created a new thread with my progress, so as not to sidetrack the good work @robo_porsche has done. My apologies to robo_porsche.
Please submit comments related to my version on the new thread, and keep the comments here only related to his work. Thanks

 

Regarding the position of the gauge I agree it is not optimal to have it below eyesight. I had a plan to put the gauge on the left hand side of the dash. It should be possible to manufacture a holder with fixings under the instrument cluster. I was thinking of a carbon fiber shell molded to fit exactly at the left hand side of the instrument cluster. (On the outside). That way you don’t have to damage the dash and it would look nice. I put that idea on hold since it is quite a lot of work.

However, I still think my oil temperature gauge is useful. When you drive on a track, you don’t have time to look at any gauge really. Maybe a quick glance when driving straight ahead. You can also check the gauge when cooling down your engine. Not ideal, but you always have to compromise.