Hi, I hav never really understood how the fans on my 550 works. Normally a car has a thermoswitch inside the rediator and that actuate the relays that actuate the two fan motors. In addition to this, there is a current from the AC system that actuate the relays to cool the AC radiator (in front of the engine coolant radiator). On my car the fans kicks in one after the other with about a second delay or something. That is normal. However the fans comes on and off (it is a bit difficult to hear from inside the car though) but you can feel it in the voltage drop and the instrument lights is slightly darger at the blink of a second. OK. The problem is that the car is overheating when running slowly on the first two gears, even if it is cold outside (10 Celcius). That is not normal. It should stay a little over 90 deg C but my car can still go considderably higher... I wonder, is the complete cooling system then at this overheat, or is it only a small amount of coolant that does not circulate properly and giving a false picture of the real heat? The case is that the temperature drops very quickly if I go faster and the radiator recieve fresh cold air. That lead me to the conclusion that the fans do not operate properly and that the relays maybe only gets voltage from the AC circuit? As someone have stolen the owners manual, I do not have anything to refer to on this. As there is a kind of delay betwen the fans come on, there must be something that creates this delay... Is it a "black box" that understand that it have to engage each fan relay with a delay in between or what? I have to turn on the fan for the heater inside the car to reduce the engines temperature, both other days, it stays at 100-110 degrees... Bad connection to the fans somewhere is a possible thought. I am in fact willing to install two small LEDs inide the car to be able to monitor if one or both fans really run. Can the power output be taken directly from the fuse box in front of the passenger seat to make the wires shorter? Then I can see when the fans run and see if the temperature still rises.. That should not be possible. Also is it two speeds on the fans? In case yes, how does that system operate? Variable voltage? When opening the hood and listening to the fans, there is absolutely no questions wether both fans runs or not. They both run. Sorry for so many questions, but this really makes me crazy. I was at a Ferrari workshop and thay did not really have a clue. They just opened the bleed screw on the thermostat cap to see if it was any air inside the system, and there was no air there. Again, thank you...
I happen to have acquired a second 550 which had some electrical issues. One of the things I found was an intermittent fusebox. The fusebox if of very poor design that Ferrari has used since at least the 80's consisting of mylar flexible pc boards sandwiched in 5 layers. incoming into the fusebox are large 4g wires immeidately distributed into the copper circuits of just 2 traces of about 1/30th the size of the pc board. From these two small funnelded down entry points power is then sucked to all the other circuits of the car. In short Ferrari did a great thing using large 4g wire to enter the box but then builds instantly high heat forcing all that charge through tiny wires. Add to that the passenger footwell temps behind the firewall and behind the fusebox coverplate in the 150*F+ neighborhood! So there is no surprise that these fuseboxes take a hit. They fail in increasing resistance in circuits and shorts and open failures. I am currently testing a solution which rewires the entire fusebox with 475*F milspec wire that was over $1.50 per foot. If this works all the fusebox problems and the daisy chain of problems they cause will be solved since Ferrari refuses to fix these problems just like we have had sticky interiors since the late 80's as well too. Specifically to your question of fans here is a bit more data and some things to check out. High resistance makes high heat and things run slow and fail. The Euro and the USA 550 use 40 amp fuses for each fan circuit as evidenced by the fusepanel door chart. The workshop manual shows these same fuses as 30A. Somewhere there is an error. In the fuse panel remove and inspect the blue and the green connector for a pair of burned wires or melted or burned connector plug. It is obvious if you have it. iirc the blue blue has two large guage ble/green wires next to each other which are the fan wires and the green plug is is the two wires paired at the driver's side of the plug. It is a joke that Ferrair has this giant 4G paired hot wire entering the fusebox then thin foil pc circuit then 2 large wires in plugs exiting to go to the fans. The bottleneck is the fusebox. That makes heat and a good failure point. So check yours. Then I would start by direct wiring 12V right to the fans to inspect them for action. I actually think that for this circuitry we would be better off at 30A as listed in the WSM and find fans of lower amp rating or even rewire the fans altogether. I will reserve judgement on that statement until I have inspected my other 550. cribj (john) has done a lot of research on the 550 cooling system as he has a complete solution for high ambient temperature cars. He may have ideas and more comments about the 550 fan system. That said you have made a diagnosis of the fan system being a problem in your car. But there are many potential sources of cooling problems in general. sometimes it is marginal function of more than one thing that make for a failing system.
Sounds as though you may have air in the system or possibly a sticking thermostat. Even if no air/vapor were released from the bleed screw, there still could be air trapped in either the left or right heads or water manifolds. I would elevate the front of the car so that the bleed screw is the highest point in the system, then bleed the system with the heater running full bore at its hottest setting. The small bleed hose from the radiator could also be plugged, as well as the bleed hose from the rear water manifold (under the intake manifold). All these are common, well known issues with these cars. There are a number of "cooling threads" and posts here, with diagrams, etc. how the fans work. Have a search in this subforum using "cooling". Here's one thread: http://www.ferrarichat.com/forum/456-550-575/379604-how-hot-does-your-456-550-run.html?highlight=cooling
Thanks to the both of you! I have just read the complete thread that you Cribbj posted. By reading the thread, there seems to point out a few things: 1) The radiators will over time (10-15 years) be either clogged inside or they will at least loose some of its cooling effect. Especially when the engine is idling (low water flow). 2) The fans are either a) not powerful enough (the motors can start tu run slower (as in electric window motors / the windows runs slow up and down. A friend of mine opened the motor and cleaned it and it then ran fast again as if the motor was new!) 3) The size of the radiator is somewhat small for the eninge for stop and go traffic as it is solely dependant on the speed of the wind that the fans create. The temperatur drops instantly when going 40 mph. and faster. 4) The thermostat also need to be checked or replaced. Another thing is that Ferrari make engines of aluminium. Of course it is for weight purposes, but the aluminium also transfer heat much faster than steel and you can then produce more horsepower as the engine will not overheat (when running fast). From these points, I think it can be worth the job and flush the radiator with some kind of acid. Water neutralize acid, so it should be sufficient to flush it with much water afterwards. From my point of view, this is better than adding "radiator rinse" treatments as it will alway stay in the engine without flushing the system like 6 times. It will also be more effective when having a stronger solution. In a perfect world, the radiator should of course not be right in front of the engine... It makes the engine warmer and slows down the flow of air.. But it is of course in the front of the car that the flow is at its most.
Aftr reading about the different possible reasons for overheating, I decided to take the car out and look at the radiator. It is in fact a bit strange that no one really talks about cleaning the radiator on the outside, as I was a bit surpriced when I looked at the radiator through the grill.... There is typical "14 years of road dust" when looking at it.... I soaked the radiator (also the AC radiator) with degreaser and used a pressure cleaner gently. Two times. You need to unscrew the grill to get better access. Very easy, six screws and it comes out. Thn I pressed the STOP button on the heater panel to cancel the fans from operating based on signals from the AC system. Then let the engine run at idle. After only a short time, the fans kicked in right after each other when the needle rised to about 100 degrees Celsius (bout 210 fahrenheit). Then the temp went slowly down to 90 and then started to rise. And so on. In stop and go traffic, at an ambient temp of about 5 degrees (something like 40-45 F), the car's temp. is somewhere between 90 and 100 deg C. It is rather strange that the car really need to big fans to cool itself when at idle when it is so cold that it is close to the freezing point............. I think the car should hav had an extra radiator at the right side of the rear wingd like the one for the oil. It make no sence to have two fans on and wear the alternator out 10 times quicker than really needed! I think the cleaning of the radiator should be done in the same time as cleaning the eninge compartment. It will over time be cleaner as the degreaser will get better into the dirt. Or even better, to remove the radiator and clean it properly.
Most of the problems with Maranello radiators come because the coolant was not changed frequently enough early in the car's life and deposits have built up inside the radiator. Those deposits do not transfer heat at all, so radiator efficiency is rapidly lost. John Cribb has come up with some ways to improve cooling efficiency on the 550. One way is to use a 575M waterpump impeller with a smaller pulley on the pump. Another way is to fit a tighter fitting shroud, which the Skunkworks sells, I believe. A new, custom built radiator is another option. Another owner (Dave?) fit an extra steam escape line that helped, too. Do a search here for more complete information. Note that nowhere in the owners manual or workshop manuals does it tell you to change the coolant in a Maranello. Some owners have had luck with an acid flush, but have to be careful with that. Nasty stuff and you want to get all of it out afterwards.
F456M: At those ambient temps, and if both your fans are working, sounds like blockage. Could be the thermostat, but you say it runs cool at speed. Have you replaced the small (6mm ID) coolant hoses that run to the intake? I don't understand exactly why, but those hoses tend to clog and cause overheating. Unfortunately, they're not easy to replace but you can disconnect one end (and maybe cut off an inch or so) and inspect for blockage. Good luck and let use know if you find anything. Regards....Mark in (40C, sometimes) Houston Image Unavailable, Please Login
You probaly have also 14 years of deposits inside the cooling system that have coated all the metal parts, preventing the heat to be dissipated. It is recommended to renew the coolant in the system once a year and if you do not know when it was done last, then you should consider flushing the system. Do not use any more antifreeze mix than you really need and make sure you do not have air bubbles at the top of the radiator or inside the thermostat housing when you refill the system. Good luck, A.
Thank you I am leaning towards taking both the hoses off the radiator, and pu two new hoses down to a place where I can have a electric bilge pump and add azid and let it pump and pump to make the azid rinse and circulate and then see if the water will be dirty.We use salt qacid all the time on boats, and it really is so gressive that most things shines like new (aluminium start to corrode). So if I rise the radiator that way and then empty the solution and then pump in lots of fresh water, I am pretty sure I can rinse it while in the car but without getting cacid in the engine... Smart or bad idea?
Keep in mind the radiator is aluminum. So I would be very careful with the type of cleaning products you put in there.
Good point. Salt acid and aluminium goes extremely bad together... I will try to find something less agressive. It is worth trying as it is probably both clogged on the inside and outside. I think the fans work perfectly when the relays have power and they engage. I think the relays needs to be replaced and the power source checked. It is a bit strange that the temperature is as low as 60-70 degrees Celsius when on the highway regardless of the speed and ambient temp. Even at 200 mph, the temp is around 70 degrees. Also kind of impressing... Do I have a F1 car or what? But idling along in the town make the engine overheat. Pretty damn strange. I will check the small hose. Is it the one from the radiator to the expansion tank or the ones that are under the intake manifold? From what I can see, all the hoses under there is of a bigger diameter, something like 1/2" or so. I cans see how they can get clogged?
F456M: 24 and 47, if the Euro is the same. Looks like 47 is the hard one on the diagram...Have heard these are a "must" replace item... Original hoses are inferior.. Here's another post about this.... http://www.ferrarichat.com/forum/456-550-575/315623-coolant-reservoir-obstruction.html Good luck ....Mark Image Unavailable, Please Login
FWIW, I discovered awhile back that the nipple which hose 47 slips over has an incredibly small ID (about 3/32", IIRC), which wouldn't take much to clog. plus the nipple is steel or iron, so it'll rust eventually. Combine a very small ID with a bit of rust, and you have the right conditions for blockage and trapping air at that back manifold. The nipple has an M10 thread, so I've replaced it with a standard 1/4" NPT brass nipple, rethreaded to the proper metric thread, and I then bored out the interior to 3/16", increasing its cross sectional area 400% over the original. A common sense $3.99 solution that "might" save a $20,000 engine someday. Another case of "what were they thinking in Maranello?"
That's funny John. Ferrari has done this to many models. They like that failure point like they like SDECU's.
Hi John..."FWIW"? Had to look that up.... and it wasn't in the Periodic Table..... Worthy indeed and perhaps a mod we should all make. Couple of questions... My 456 GT has a brass fitting where the small hose attaches to the radiator (see post #8)... Did they use a steel fitting only under the intake? Is it the same size as the nipple as used in the rad, IYR? Regards....Mark
Maybe. You see we know the oem one lasts a long time. It will plug in many years but it is a simple fix. How will brass hold up? How does brass handle vibration? How thick is a modified brass fitting at it's thinnest point that's where it will fail. How does brass react to the electrolyte and other dissimilar metals? Is there a reason the oem one is steel vs brass or even aluminum like the casting? I don't know enough basic materials to answer any of those questions and there may be other's I don't know to ask. Did Ferrari have a reason or was it just available and cheap? If the brass fitting mod is a permanent fix I am all for it.
It is pretty awesome how much knowledge one can get out of something as a small thread on Ferrarichat.com... I agree the inside of these small pips are almost too small... BUT it can also have something to do with the pressure in the cooling system. I don't know, but a very thin pipe here will make the water flow, but at a very small rate/flow. I am going to replace the relays at least. And then go to the hose/pipe problem after I have cleaned the radiator and replaced the relays. To me there seems like the fans don't go on at all some times....... I really want to have a set of two yellow LEDs somewhere which will be connected to the output side of the relays' power supply to the fans (+) per fan, and a small switch to on the LEDs negative wire, so it is possible to switch the LEDs off when going fast at night. Thanks again for great help.
Mark, on my 550, the radiator nipple is steel also (just checked it with a magnet), and it's a smaller thread (maybe M8) than the rear manifold. 456M/FBB might be right - perhaps Ferrari purposely sized that nipple in the rear manifold to limit flow. From the rear manifold, the coolant goes to the expansion tank, and then it mixes with coolant going back to the water pump, so in that regard, it bypasses the thermostat. So increasing the size of the nipple might cause the engine to be a bit slower to warm up. Can't comment on the change in metal.
I just did my super duper radiator cleaning process... Used a pump and flushed through a solution of water and a strong cleaning product and filtered the water that came out. It was next to nothing dirt in there and the water flew through without any resistance. Took off the small hose "47" at the expansion tank, took a deep breath and blew through it. It might have been a small clog but I am not sure. At least there is free open passage through the hose. I also theched the small bleed hose from the radiator to the expansion tank. Later I filled up with new coolant and bled the system after lifting thenose of the car. After this, the car operated perfectly. I did everything I could to make it overheat inside the streets of Stockholm, but it never ever went beyond ca. 100 deg. C. I find that a bit odd, so it is possible that the fans have failed to start when the car has been hot. Now I want to realize my plan of having two LEDs that light up when each fan is on.
Today, the fans come on and off at different temperatures...... Sometimes they start at the usual 100 degrees or so, other times they start at more like 115 deg. C which is very close to the last line and towards the red sector. This drives me crazy as I am afraid the fans will not come on at all when I am on the phone or something else, and do not register that the temp is too high. This evening, I had a 40 min dinner stop, and the temp was abot 75 when I started the car. After ten seconds the fans came on and stopped after about another ten seconds. WHY DOES IT DO THAT? I am leaning towards thinking that it must be the AC that turns them on, but why should it switch on the cooling fans after ten seconds? The AC radiator cannot be warm or the pressure cannot be high at that time. And the outside temperature is as low as 8 deg. C. It would be great to know how the system really works.
Hi to all and F456M The temprature at my 550 is also very "variabel". Driving slow in 1st and 2nd gear (city) or standing some minutes, and the temperature will go up to 90-100°C at this weather in September Oktober (10-15°C) or up to 110°C in Juli/August (25-35°C). Drivin some hundred meters faster, the water temperature fall down to 70°C. The fans work, but they work together, i thought they have to work single, each at a fixed temperature, but i don't know this exactly. I changed some parts: The car got new silicon hoses 47 + 24 in spring, 2 new water temp sensors (Bosch) in spring, also a new thermostat 4 weeks ago. I changed the coolant liquid (BASF E30) in spring (the old was very clear after 1,5 years) and reduced the mixture also 4 weeks ago, perhaps i will reduce the mixture once more. The system should be free of air bleeds (car was raised at the front by refilling the system). But it's not really better. So I believe, it's normal that the 550 temperature is very unconstant, not like in other cars 90°C at each working/driving condition (city, Highway, hillclimb, idle, .... like my Alfa Romeo V6). Any other experiences with constant water temperatures in different working/driving conditions. Daniel
F456M- I have a 456 GT with a different ECU than the 550, but fairly sure the big cooling fan comes on with the A/C, whether the rad is hot or not.....about 10 seconds in the GT...but stays on as long as the A/C is on, IIRC...You guys should come to Houston to test your cooling.... At your ambients, I don't think I'd ever see much over 90C... John- Sure looks like a brass fitting entering the rad on my GT.... took a look under the intake but couldn't see if that nipple is steel or what... FBB- Thanks for making us think.... I suppose John and I were thinking brass would be better than steel, as brass doesn't rust. However, brass is more cathodic than aluminium and steel. So brass will make the aluminium corrode more than steel (I think). I'm also guessing the steel nipple won't rust because steel is more cathodic than aluminium, so the aluminium will corrode before the steel rusts.....leading to the conclusion that steel is the better material (than brass) for this application. Both will make the aluminium corrode, but steel less so... go figure..... Regards.....Mark
If the fans kick in so late then one of the temperature sensors (33 in the attached diagram, there are two of those although only one is visible, change them both) is faulty. One of them turns on the fans at 95C and, in case this fails, the other turns them on at 105C (which is what you're experiencing) as backup. The sensors are cheap, but the plenum has to be removed to access them and that is a 6 hours job. The fans come on early, even if the water is not hot, when the AC is on. The water might not be warm, but the gas in the AC's radiator still needs cooling. Stefano Image Unavailable, Please Login
In most modern cars the temperature gauge is set to read 90C all the time, to avoid the user getting nervous. It will only start to rise when the engine is overheating dangerously. This is also true of extreme sports cars, e.g. the Lamborghini Aventador.... My BMW does not even have a water temperature gauge!
