355 fan probem

Yes, it is triggered by the Motronic. The water temp sensor to the right of the oil filter housing is where the Motronic gets the temperature info from. If it stays on, perhaps a sticky fan motor relay? Try swapping it with the left side fan relay.

 

I take it the right fan is coming on at 90 degrees celsius (about 200 degrees fahrenfeit)... Once your engine heats up, does it come back down?

How did you resolve your past issue with the left fan only coming on for a few seconds? After putting my engine back in I have the same issue. Changing the thermo switch and swapping relays did not change anything.The right fan is operating properly and only comes on when the oil temp hits 200 degrees.

I'm thinking the thermostat is bad or system is not bled properly. I'm hoping to try and bleed my system tonight from the screw on the thermostat housing.

 

I believe it is item 40 in this diagram - http://www.ricambiamerica.com/parts_catalogs.php?M=FE&P=&V=diag&I=1464.

There's a good picture of the sensor on page B69 in the workshop manual (at least for my '95 2.7), figure 52, item 16.

The l.h. fan cycling on for 5 seconds at a time just doesn't seem right, even though others have the same experience...

 

There are some good pics of the sensor in this thread - http://www.ferrarichat.com/forum/showthread.php?t=159777&highlight=355+coolant+temp+sensor

 

See my post #2 please.

 

The right side fan is triggered by the Motronic...the Motronic senses the WATER temperature from the water temp sensor to the right of the oil filter housing on top of the engine. Oil temperature has nothing do with activating the right side radiator fan.

 

Your confusion is the workshop manual specifies that the right side radiator operates based on the lubrication system cooling in section B71 of the WSM. If you read the section in B71, it specifically states the radiator fan is triggered based on the NTC water sensor when the sensor reaches 95 degrees C.

Apparently no one has every gone back and read section B71, so this confusion that the right side radiator is triggered by some non existant oil temp sensor (some even mistakenly think it must be the oil temperature gauge sensor), and it has been perpetuated on this forum for a long time. Sorry if you read one of those threads. I have tried to correct them when they come up.