dead oil temp guage

Very simple, it's at the front of the trans pan.

Work quickly and you won't even need to drain any oil.

 

I'm in the middle of the same operation. The sender P/N is 107576 (for a 1988 328 as well as other 3x8 models per ferrari owners site parts catalogs). Ricambi America has the best prices. It just screws into the oil pan (to the left of center). Mine has some sealant on it - teflon tape should work fine here. You will have to jack your car up to get to it, and use jack stands, don't just rely on the jack. BTW, spray some cleaner on the area before you take it out to make your life easier and prevent grime from getting where you don't want it. Good luck.

 

It's one of the least expensive parts you'll ever buy for a Ferrari engine!

 

The sender unit could be bad but it would be the least likely candidate in my book. It is really nothing more than a resistor. Have you checked anything else?

 

Also the sending unit is covered with a rubber boot. If the boot has come off or been dislodged -dirt and grime will get into the contact points and this could also be part of the problem. Lastly, have you driven the car and properly warmed up the engine? Sometimes it takes quite a while on my car to even get the oil temp gauage to move. Usually takes about twenty minutes.

 

Ditto to what Erich posted -- you can't just assume this:

Do this test:

1. (With the ignition key "on") Unplug the wire from the sender -- note gauge reading.

2. (With ignition key "on") Touch the (unplugged) wire going to the sender directly to ground (like the nearby bare engine) -- note gauge reading.

If the gauge changes from the "min" to "max" reading for the two conditions -- good sign for gauge/wiring/power and bad sign for sender.

If the gauge doesn't changes from the "min" to "max" reading for the two conditions -- bad sign for gauge/wiring/power.

 

Or a faulty gauge itself.

 

Being an electro-mechanical device (voltmeter) there is more chance of a bad guage than a NTC or PTC sender. However, on Italian and British cars a bad connection (bad ground, broken or dislodged wire or terminal, bad crimp on a terminal, corroded terminal etc.) should always be the primary suspect. It's so often the most likely cause and the cheapest fix also.