355F1 - Oil Temp Gauge / Clock Swap

This swap is for the F1 models that did not come with an oil temp gauge from the factory. It replaces the clock on the center dash pod; but basically you can replace any of the three existing gauges in there using the same procedure. But I really cannot see why, as the clock is probably the least important one in there anyway.

It was actually very easy to do, with only 3 major steps, and is not as difficult and involved as I thought it would be. This assumes you have some basic mechanical and electrical skills, such as stripping electrical wiring, splicing, cutting and crimping connectors. That said, I do not express nor do I imply any warranties or guarantees, and "your mileage may vary." ;-)

Here are the parts that I used and steps involved:

1. Ferrari F355 oil temp gauge - part number 167433. I used the UK version as I figured it is less expensive than the US version (part # 167432) for some reason, and also read in deg F. There is another version (Asian or AU) that is a lot less expensive but I think that read in deg C. I found one on eBay for $50 so I said what the heck and might as well try it. I really don't understand the big differences in pricing for what is essentially the same thing.

2. Gauge wiring harness - part number 157492. The light bulb socket that goes into the oil temp gauge is different from that of the clock, so unless your oil temp gauge came with its own socket (mine didn't) you will need this harness to cut off and harvest one of the light bulb sockets to use in the oil temp gauge.

3. Oil Temp thermistor - part number 107576. Make sure you get the thermistor with only one wiring terminal. *Here is the key to making this whole thing easy to do with practically no down time: we found that the size and thread of this thermistor is EXACTLY the same as that of the oil tank drain plug. The only difference is that the surface of the thermistor that mates with the tank is slightly rounded, so I had mine machined flat so that the drain plug washer fits just as it would with the drain plug. Just bring the thermistor and a new drain plug washer to any machine shop and they'll do it for a few bucks. This eliminated the need to remove the oil tank and weld a new bung underneath.

4. Oil Tank drain plug washer - see #3.

5. Round crimp connectors (4-5 pcs)

6. 1/4" female spade crimp connector

7. Hook up wire

8. Zip ties

Installation of the new oil temp gauge is pretty straightforward, and is a direct swap with any of the center dash pod gauges. I chose to remove the clock from the center dash pod and swap that out with the oil temp gauge. You will have to remove the stereo head unit, then six tiny screws underneath each level or section, and the whole center piece should pop off. You can then disconnect the harness to remove the piece from the dash.

There are two tiny screws to remove that secures a retaining ring that hold each gauge. Disconnect the wiring harness of the clock and remove the two screws that hold the retaining ring of the clock. Remove the clock, and tie wrap the harness that goes to the clock to the rest of the wiring, as you will not need this for the oil temp gauge. I'd keep it handy and attached, though, in case you want to reverse the procedure and reinstall the clock in the future.

Installation of the oil temp gauge is the reverse of the above procedure, reinstalling the retaining ring and the two tiny screws.

Now for the wiring. Looking at the back of the gauge cluster, there are three terminals behind the gauge. The one at the left is (+), the one in the middle is (-), and the one on the right is the signal from the thermistor. I crimped a couple of round connectors to the ends of a short piece of hook up wire, and hooked up power to the corresponding terminals of the other adjacent gauges. Leave the third terminal unattached for now.

Take the factory gauge harness and cut off one of the light bulb sockets (the three sockets should be identical; if not, make sure you choose a socket that will fit the opening behind the gauge), leaving a short length of wire. Splice one of the wires from the socket to the yellow wire that goes to the other light sockets. Attach a round connector to the other wire and connect it to a ground, using a middle terminal of one of the gauges. Remove the light bulb socket from behind the clock, and take the light bulb and reinsert it into the new socket, making sure you keep the green filter installed on the bulb. Insert the socket into the oil temp gauge.

Now place the car on your jack or lift, and remove the underbody panels underneath the engine. Remove the drain plug from the oil tank, and let the oil drain. Now might be a good time to change your oil, or if you just did it, you can choose to save the oil and reuse it. Place a new washer onto the modified thermistor, and install it in place of the drain plug. Make sure you torque it properly, without overdoing it or you might strip threads.

Now, there is an extra wire with the proper connector and rubber cover to go over the thermistor, that is just dangling somewhere in the area. I assumed this was used for the factory oil temp gauge system, but I searched extensively inside the passenger compartment, around the area of the ECU (passenger side), and the alarm and F1 computers (driver's side) and could not find the corresponding lead. The only thing I didn't do is disconnect the ECU harness, and I suspect the lead goes in there somewhere. Please let me know if you have knowledge of where this extra wiring leads to.

I gave up on chasing this lead and decided to just run a new wire from the thermistor to the gauge pod. I found a grommet just in front of the fuel tank, in the central area that goes into the passenger compartment. Remove the center console ashtray and switch panels, and run the wire through the center console, underneath the carpeting, and up unto the center gauge pod. Cut off any excess wiring, and crimp on another round connector. Attach this to the remaining third terminal on the right side behind the oil temp gauge. Tie wrap the harness neatly and tuck it into the dash. You may want to hold off final assembly until after you have tested your installation.

Going back underneath the vehicle, cut off any excess wiring off the wire to the thermistor, and crimp on an insulated female 1/4" spade connector. Attach this to the thermistor. You can wrap the connection with electrical tape, or shrink wrap tubing. Tie wrap any loose wiring. DO NOT FORGET TO REPLACE THE OIL YOU HAD JUST DRAINED BEFORE STARTING THE CAR!

Turn on the ignition, without starting the car first. If you made the power connections correctly, you will notice the needle of the gauge rise up ever so slightly. Go ahead and start the car and let it warm up. You should notice the oil temp rise up slowly as the engine warms up.

If everything seems ok and the oil gauge appears to be working, reassemble the center pod and reinstall the 6 retaining screws. Reinstall the center console switches and ashtray. Reinstall the underbody panels.

So now, the only difference is that every time you do oil changes, you will have to disconnect the wiring from the thermistor, and remove the thermistor to drain the oil. But there is no cutting or welding, and your 355 will not be harmed in any way! And it is completely reversible, and that OEM look is maintained!

This completes the install. Let me know if there is anything you can add, or improve. Pictures to follow. I'd also like to thank Shawn of Eurospeedz for letting me play with various loose parts at his shop, and for doing an awesome job on my major service (I know, shameless plug). And thanks to Goth for the referral!

Good luck, and I hope this helps make our awesome car more complete and enhances your ownership experience!

Cheers

 

The gauges and the wiring behind them...
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The thermistor, washer, drain plug, and thermistor installed into the oil tank...
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Wiring into the passenger compartment. Found a grommet just forward of the gas tank, in the central area of the body. First picture is taken underneath the car, the second from inside the passenger compartment.
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Ask and you shall receive...
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You're welcome! I've been wanting to do this mod for many, many years now myself. Glad I did it, don't miss the clock one bit!

 

You're welcome and thanks!

 

Thank you, Scott! I've been a long time member of this group, but I do not post much. I just thought I'd start to get back into it through this humble contribution.



Alex

 

5th paragraph down after the numbered bullet points, in the OP. It uses the same light bulb as the one from the clock.

 

Then you are more than halfway there clearly Ferrari had a bunch of left over oil tanks from previous years that they used on the early F1s.

Here is a clip from my original post:

"Now for the wiring. Looking at the back of the gauge cluster, there are three terminals behind the gauge. The one at the left is (+), the one in the middle is (-), and the one on the right is the signal from the thermistor. I crimped a couple of round connectors to the ends of a short piece of hook up wire, and hooked up power to the corresponding terminals of the other adjacent gauges. Leave the third terminal unattached for now."

That unattached terminal is what connects to the thermistor (i.e. oil temp sending unit). I think there is a wire already laid out in there that you can hook up to the sending unit, but you will have to trace it into the passenger compartment and see where it leads. I could not do that on mine, so I just ran a new wire from the sending unit to the gauge.

So all you have to do is get an oil temp gauge and replace that clock!

HTH, let me know if you have any more questions.

Cheers

 

No, I don't think the ECU is reading oil temp... on my car I have that extra lead underneath the oil tank that is just dangling there...

Does the temp sending unit have a lead actually attached to it? Hard to tell from the picture.

[edit] ok I see where the lead is attached. In that case, what I suggest you do is take out the gauge cluster and see if you have an extra unconnected lead in there, that's probably the lead from the temp sending unit. See if you can determine the color coding of the lead from the sending unit, and see if you find that same lead behind the gauge cluster. You might get lucky.

Best case is that you will just have to swap out the clock with the oil temp gauge, connect the wires and you're done. Worst case you will just have to run an extra lead from the sending unit to the gauge.

 

No, I never did. I searched until it got dark that day and couldn't find it. But the wire that came from the dangling terminal should lead to somewhere... I suspect to one of the wires on the different ECUs. But nothing matched up and I tried putting a 1.5 voltage to the wire and tapping different wires inside the passenger compartment to find out. No luck. It was easier in the end to just run another wire.