I did search and read a few of the threads on this but didn't think it answered the question completely. Under normal driving, my oil temp stays at middle or slightly above. Under fairly hard driving through the canyon the other day, I was hitting just above the next tick up. Is this okay? Should I check the thermostat for the oil cooler? Pic for referance. Image Unavailable, Please Login
On a 348, the oil cooler fan will come on at about 200 F, possibly same on the 355. The only way to check whether your fan is working is to look at it when the oil temp is at more than 200 F. Otherwise, quality synthetic oils are good for up to 300 F (or more), thus the red line 300-320 F on the gauge.
Same. The trigger point is 95C, so 203F. It's a water temperature sensor. Would this be close enough to (gauge) oil temperature?
Yes, it is very close to the setting for the 348's oil radiator fan to come on. After checking the diagram, I can see that 355's oil radiator (unlike the 348's) is cooled by the RH water radiator fan and the oil temperature is regulated by a mechanical thermostat valve. If the fan is working normally, and if the oil temp control is considered inadequate, then the thermostat valve could be the suspect (not opening or not opening sufficiently) or the oil radiator could be partially clogged by some debris.
