Quick question Are both fans supposed to cycle at the same time, or does the left (drivers side) cycle without the right side going on?
Just checked the manual, and the right side fan is controled by another thermostat. It's oil temp that causes the right side fan to turn on. Left =water temp., Right = oil temp. I feel better now
Hi Dave, Both fans can come on via water temp the engine ECU can turn on the right fan also. You A/C system will also turn on a fan too the left I would assume since that is where the condenser is(behind the H2O rad.) Regards, vern
Yes, there are 3 fans on 348s 2 coolant and 1 oil cooler. The coolent fans come on together via the sensor in the coolant. The oil one comes on buy its own thermistor.
You guys are confusing the 2 coolant fans from the oil fan. 355 has 2 coolant fans triggered as Vern said and one oil fan triggered as Dave said. Duh. Scratch that. I am thinking TR. The 355 is as Vern said. They cycle at different times. The left is turned on by Motronic and I think oil temp can trigger it as well but it would be unusual for oil to be that hot and not the coolant.
I don't know what the issue is but I have seen the plastic 355 fans fail where they lock onto the electric motor shaft. In that case the motor is running but there is no significant air flow through the radiator.
Basically I have the left fan cycling, the right fan has not come on. This on the first start up after my DIY major service while the motor is idling for ten minutes to reset the ECU. (it runs,....... I'm so excited ) I'm wondering if the oil temp has to be at a certain range for the right fan to come on, or do I have a problem with the right fan. The left fan cycled about every minute or so, the right fan never came on.
That would not be uncommon. If the H2O temp is getting over 200 you have a problem. If it is not that hot I would not expect the rt fan to come on.
The Left Fan (Drivers side) is the primary fan. It will come on if: 1) The water temperature gets to high OR 2) You turn the Air Conditioning on. I use that trick (turn AC on) when I am on the cool down lap at a track event to help cool down the car. The Right Fan is a backup, it only comes on if the Left Fan can't keep the water temperature down or if the Oil Temperature gets really high. Both Fans will not run at the same time. I run my car for 15 to 20 minutes during the Winter months when it is hibernating. When I do that the engine gets hot enough that the Right fan will come on.
Not TOTALLY CORRECT Oz, the fans can and do both run at the same time if the left is running because it's thermister tells it to and the engine ECU can turn on the right fan(along with the left fan running) if the engine isn't cooling down such as in traffic with the A/C on or it's just too hot of a day. Another example my 355CH runs both fans, when the left hand thermistor turns on the left hand fan it also turns on he right fan or I have a switch that I can maually turn on both fans at anytime. regards, Vern
I have discovered (in winter months, i.e. air is cold) that whilst idling only the left hand fan operates because it can keep the water temp OK all by itself and because whilst idling the oil temp dosnt get too hot. When driving its a bit random, either fan or both can come on I think (difficult to tell when actually driving) So I would say all appears normal ferraridriver Reading the manual pages above - they suggest to me that the LH rad is water temp controlled and the RH oil temp. 88deg H2O=left fan on, 95deg OIL=right fan on... I guess the water getting really hot means the oil gets hot anyway so both fans then activate - potentially worrying if only the right hand fan comes on I guess! (ie. cool water, hot oil!).
NO! As already said, both fan are driven by WATER temperature: - the left one by a thermoswitch (88/82 °C) at the top of the radiator itself ... and also by A/C according to the pressure in the circuit (the A/C pressure switch is at the top of the dryer) - the right one by a thermistor (NTC) connected to the Motronic wich measure the water temperature when it exits the heads. Fan is on when the temperature at this point is above 95°C. Because of the different locations of the sensors, and the different thresholds, all the combinations of fans operation may occured (none, both, left only or right only)
Well put Eric but, one thought I don't think the right fan can be on by itself. unless the temp sender in the LH rad. was not working. The ECU triggers the RH fan at a higher temp than sender in the LH is set at. So theoretical if the RH fan is on the LH already is running. Did that make any sense? hahaha. What do you think? The oil temp has no effect on turning either fan on directly, only indirectly thru the sensor in the water cross over pipe on the engine if the oil got hot enough to rise the water temp. Just a side note on oil coolers on 348 and 355s, the 348 has a cooler about half the size of the 355 but, has a fan operated by a oil temp sensor, the 355 has a cooler that is twice the size and no temp operated fan but a thermstat that contols oil flow thru the cooler. A 512 Boxer has no oil cooler at all which I always found interesting, there must be enough oil in them reculating around to disapate excess heat. Regards, Vern
You are right. I glossed over that line. Yes they can and do run at the "same time" but triggered independantly.
