NEW, UPDATED: F355 Radiator Fan Information

I just wanted to say a big "Thanks!" to JR from The Fan Man. JR is Jack's son, and he did a huge favor for me leaving a pair of 2049 fans for me after hours. I was in a hurry to get my 355 back on the road for a beautiful SoCal drive over the weekend and JR left a pair of fans with a neighboring business on a Friday night. Got the fans installed and enjoyed my cruise through Angeles Crest Hiqhway.

They are no longer stocking the 2050 fans, but they will special order them from Spal. The 2049's worked just fine for me. Splicing the old connector onto the 2049 is a little more work than the 2050 that uses the correct connector for the 355. But one advantage to the 2049 is the tab that holds the stock connector onto the fan housing is missing on the 2050 as stated by Jevs in this thread: http://www.ferrarichat.com/forum/showthread.php?t=377986&highlight=radiator&page=2 I know it is not a big deal to use a zip tie, just finding the silver lining...

I've had the car out on a couple of hot days, over 100 degrees F, in stop-and-go traffic, and had no issues with the 2049 (vs. the oem SPAL 30102113) fan. The 2049 kept the temp at normal (around 200 degrees). I did not notice a difference in runtime for what it's worth. Just another data point for the Spal 2049/2050 fans in a '95 F355 GTB 6 speed manual.

 

I cannot believe that nobody has suggested wiring the fans with external relays, powered from the battery power point in the engine bay or the starter wire, triggered by the original fan circuit.

This way the fans would get sufficient current (and quite possibly perform better) and the OEM fusebox load would be reduced to whatever current necessary to activate the relays.

We do this on many cars that have weaker fan circuits frequently, mostly when adding aftermarket fans, the 355 seems like a perfect candidate for this.

One could even go a step further and use an aftermarket fan controller to trip the fans at any temp. you like.

 

355CH uses manually controlled fans

 

I have a question... we all know that the left and right fans turn on at different times, with the left (driver's side) fan turning on more frequently at full speed, and cycles on and off as the coolant heats up and cools down. But occasionally, the right side fan turns on at full speed as well, while it turns at reduced speed most of the time.

What are the parameters for the the function of the right side fan? When does it turn on, at full and reduced speed?

I have heard some people wiring their left and right side fans so that they both turn on at full speed simultaneously, at the same time the left side cycles. What are your thoughts on this? I would think that this would cool down the water temp much faster. I have seen it wired at the fuse box, jumping the low current side of the two fan relays so that the fan still draws its main current through their respective circuits, so this should prevent overheating at the fuse box?

It also seems that when the AC is turned on, the fans are overridden and turns on constantly, is this the normal thing to happen? How is the thermoswitch overridden to turn on the fans when the AC is turned on?

And is it normal for the fans to turn on right away when the ignition is turned on, but engine off? Even when the engine is cool (i.e. not yet at operating temp)? If this is not normal, what could be the cause for this to happen? Could a defective thermoswitch be the culprit? My car has been acting like this lately, and I hope it is as simple as a defective thermoswitch.

Thanks in advance!

 

I believe the right side fan runs on two speeds, low and high, if I am not mistaken. I do notice it running at low speed occaionally.

Where is this AC switch located? I think this is the culprit. The other morning, the fan ran normally all of a sudden, as in it was off at cold start up, then cycled on and off after the engine reached operating temperature. But when I activated and turned off the AC switch on the center console, the fan stayed on since, even on cold starts. And it did not cycle after that. This never happened before.

OK.

My fans started acting up when the AC evaporator/heater core was removed and replaced to fix a coolant leak recently, hence my suspicion that the AC system is the culprit somehow. I rechecked installation of the evaporator/heater core assembly and all the connections, and everything looks fine.

I just ordered a radiator thermoswitch and will swap that out, we'll see. If that does not make any difference, I will look towards that AC fan switch.

Thanks, Alex

 

Curious about my fan behavior. It just seems to come on in really short bursts, never running very long at all. Is this normal or is my fan switch on the fritz. I'm referring to the LH radiator fan.

 

Genteleman, I am happy to help where people have helped me.

The A/C fan (right side) is controlled by a switch on the A/C drier, which is right next to the battery cutoff switch. This switch is called a "trinary" switch, it has three functions, one of which is turning on the relay that turns on the fan. (the relay is on the relay board in front of the passengers feet).

The trinary switch also will not allow the A/C compressor clutch to engage if the freon is low, or if the pressure is too high (plugged hose or too much oil).

I have considered it normal for the water radiator fan (left side) to go on in shorts bursts, especially in stop and "go fast" traffic where you are going fast enough between stoplights to let the airflow cool the radiators.

Typical figures for a trinary switch: no compressor below 30 psi. No compressor above 400psi. Fan turns on at 250 psi.

Please note that I am self educated about A/C because I got sick of being ripped off.

 

Ya, I'm just talking about sitting in the driveway idling. I can't really hear what the fan is doing driving down the road.

 

Mine does that early in the day, and seems to not do that later on.

 

+1 ....... I have seen at least one fan run 'slow' when it switched on and it was because the fan motor was going bad. As far as I know the 355 fans are on or off and only run on one speed when on.

That is normal ........ if your temps stay within factory spec ...... then all is well

Your coolant temp gauge should always be between 8 and 11 under all conditions (after full warm up) per the manual ........ use this diagram for reference.
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Thanks for the info. Now I know my fans are not operating normally.

Here's what is happening: The fans start out as normal, off when ignition is switched on engine off, and cycles on/off as the engine warms up. It behaves like this which is normal, and the engine temp is within normal range.

The fans behave normally, until I turn on the A/C. The left side fan (and maybe the right side, too, I am not 100% sure) turns on, and stays on. But what seems to be not normal to me is that after engine shut down, and every time I switch on the ignition (engine off) even when the A/C switch is off, the left fan turns on immediately. It does not matter whether the engine is cold or hot, the left fan turns on immediately. And when the engine is started, the fan stays on and does not cycle between on and off like normal.

And it gets even stranger... after a few days, the system seems to "reset" itself and the fan behaves as normal again, i.e. does not turn on immediately when ignition switch is turned on, and cycles between on and off when engine warm. Until, that is, I turn on the A/C, and the whole thing happens again.

I have been keeping an eye on this these last couple weeks, and this is the pattern I can come up with, and it has been pretty consistent.

There has been some work done to the A/C and heater system recently, and has been acting this way since. We looked for the source of a coolant leak in front area of the car, and traced it to the heater core inside the Evaporator/heater core unit. We took that unit out, took it apart to test the heater core, and put it back together. We had to release the freon to take out the unit, and then recharge it. The A/C is strong, and the leak appears to be gone, but I now have that new fan behavior. I double checked all the connections, and everything seems to be OK. The Climate control system appears to be functioning properly otherwise.

What could have gone bad in the A/C system to cause the radiator fan(s) to behave differently after the A/C heater service? I have a new radiator thermoswitch, but have not installed that yet, but now I somehow think that is not the problem.

Thanks in advance.

 

From what you are saying I would suspect a bad relay somewhere that is sticking closed. The contacts could be so bad from arcing that they maintain a closed circuit even though the relay is not energized, then after a while and a few bumps in the road, it pops open.
That's my best guess.

 

As mentioned, a shorted relay, but there are two other possibilities:

The green wires from the aforementioned trinary switch run under the ABS brain bracket and are unsecured. I have seen them pinched. (picture below)

Also, on cars that have "melted" the hidden A/C fuse, it seems like the blower motor relay gets worn out, in addition to the wires. The overheated wires can melt together. It is easy to trace, in front of the passengers feet, under the trunk cover.
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Hmmm, thanks. I will check those out. Maybe worth the cost of those relays just to change them all out altogether. Though I did try to swap out the left and right fan relay to the same effect, that is, the left side fan still stayed on when ignition was turned on with engine off.

 

I will check that out, too. The relays in the passenger well fuse box did get really hot when the fans were on, so melted wires are a possibility. Thanks!

 

Many 355 owners have to know that when the fans start blowing the 30amp fuses that they have to replace the fans as they are begining to draw too much current. Replacing the fuses is just a temporary relief and will eventually lead to the fuse panel being screwed up(the footwell one) and short cycling of the left fan. These fans are only about $130 each at the fan man. The OP seems to have something else going on and my first guess would have been the relay is sticking but it wouldnt surprise me that he has a fuse panel problem. Dave Helms has solved this problem in other models and hopefully he will do the same for the 355 soon. So many 355s are short cycling the left fan that many think its normal when it is not. Goth has posted a very nice diagram of the heat guage above. Most 355 will run up to between the 11 and 12 and then the left fan kicks on.(the right fan will run at different times and lengths depending on a/c ect) The left fan should run untill the needle gets back down to around the 9. When the fuse panel is screwed the needle will range up an down between 10 and 13 with the left fan short cycling ie: on for 3 to 10 seconds and then off for 30 to 40 seconds.

 

Funny how my car has about 50k miles and never a fan issue... still stock fans and my car lives in Puerto Rico... which means 70's and 80's .... sometimes 90's and it always runs in the 175-180 degree perfect.... takes heavy traffic and 90 degrees to get it to 190 or more...

 

It has nothing to do with the ambient temps but more to do with unsealed oem fans that get dirt into them and cause them to slow down and draw more when kicking in. You might have gotten lucky and not much dirt or water has gotten into yours.

 

Yet another reason not to drive these cars in the rain. I even stuff plastic bags in the side scoops before washing.

Very informative thread.

 

Ferraris don't melt when a few spots of rain hit them. I live in the UK, so if I only drove the car in the dry, I'd do about twenty miles a year! The manufacturer of the OEM fans states that they are for track/race application. Swap them out for a more durable road version and drive in the rain.

 

My left fan is cycling between 9 and 12 in traffic. Don't hear the right coming on. The fuses are fine. The left fan comes on at about position 12 for 10 seconds and off again. Should I be concerned? If so do what? Replace fan?

 

If it comes on for only 10 seconds, how does it cool the temp down to position 9? Or, am I misunderstanding something .