Evening, My 550 started to overheat during its annual MOT test. The day was hot for the UK and it stood still idling for a while the temp light started to come on and then you get all manner of other warning lights as it has a tantrum. Last time it did this was on a track day in similar temp conditions. Once moving the air flow through the radiator brought the temp back down. When home it got hot again but with the bonnet open and both fans working the temp dropped slightly and no longer appeared to want to over heat. The "gap" in the bumper isnt huge so air flow to the rad isnt great at the best of times I have ordered a new thermostat, and will change the cheap sensors, Ferrari dont make them and i will find cross referenced parts. The Temp sensors look a pig to change as under the intake manifold but... Where do the fan sensors live ? Coolant isnt old and the car is fine other than in extreme heat. thanks
The temp sensors are the fan sensors by telling the ECU the coolant temp and the ECU turns in the fans. If both fans are running, it doesn’t sound like the sensors are a problem unless the fans are coming on late, in that case, the left sensor may have failed. Image Unavailable, Please Login
The ECU turns on the fans when one of the sensors indicates 95C. If this sensor fails, then the fans are turned on when the other indicates 105C. The sensors are cheap but the plenum has to be removed to access them. Make sure that the radiator is clean on the outside, run a lower antifreeze mixture (mine is 30%) and consider taking the fan relays out of the fuse board: https://www.ferrarichat.com/forum/threads/550-engine-cooling-improved.622609/ Stefano
The left side sensor triggers the climate control ECU to turn on the fans, the right side sensor (if the left sensor fails) triggers the Motronic ECU to turn on the fans, so yes I guess the AC pressure switch is probably involved. My fans will start cycling on and off within a minute of starting the engine cold with the AC switched on. If the AC is off, the fans won't come on until the coolant is around 185F (according to the gauge).
Graham, you said your fans were running when the car got hot, so I suggest trying the following before removing your intake manifold. With a cold engine and climate control switched off, start the engine and watch the coolant gauge to see when your fans turn on. If they come on just below the 190 mark, your left sensor is likely working ok and the sensors are not likely problem. If the fans turn on, but not until somewhere closer to 200F, it is likely that the left sensor has failed and the right sensor is still working as the backup. In this case, the fans turning on late will make it harder to bring the temp down in hot weather, but if the rest of your cooling system is in good working order, the temp should still come down. My car on a hot day (30 celsius) in stop and go traffic will show a coolant gauge temp fluctuating between 170-190 as the fans cycle on and off.
I live in Arizona in the US - where it is really hot and had all kind of issues with my 550 engine cooling with the same symptoms you described. I changed out all the temp sensors, thermostat and hoses - did not do anything. I switched to a mixture of 100 water and no-rosion. which helped a little but not enough. Then I got ambitious and changed out the fan shroud for a 575 shroud, put in new fans, and powered the fans off relays connected direct to the battery. That worked - really well and when the fans turn on it sounds like a hurricane. Before doing that it was hard to tell they were on. I am not sure, but if I had to guess I would say that putting in those relays (Spal sells a kit) is what helped the most. The basic idea is that you use the signal that currently powers the fans to control the relay(s) with power coming direct from the battery going through the main relay contacts. The fuse board in these cars is highly suspect - one thought is that over time the current going to the fans becomes limited due to bad connections, limiting etch runs, old relays, etc.
There is a solution to the question being asked.... https://www.ricambiamerica.com/as1-456-550-cooling-harness.html
You really do not need a kit. Two relays, some fat wire and two fuse holders all from Amazon. Make sure it it all waterproof. Run the relays in parallel Crimp together and heat shrink the crimps. I pulled my power off the alternator post that is about 12 inches away. I also got a 10 second delay relay for the second fan which triggers off the main fan switch. No worrying if it the second fan comes on or not. Car stays really cool. It is all tucked up and attached to the secondary air lines by the radiator.
I have built a lot of harnesses, mostly for race cars, but Aerosurfers kit is really well done and not worth creating a parts chase for the little money you save. It's a 15-minute install if that. I would think Ricambi could supply it through their UK connection. I'm adding the larger Spal fan this week which this allows for. The thing is, you save the fuseboard and maybe get a little more flow from the relay kit by not having the 12-volt supply sag, but the real payoff should be from the 2500 cfm fan (or fans) that need the larger relay and fuse to operate.
+1 As Ryan says, normally, the HVAC ECU controls the fans according to its demands and the temperature sensed by the LH bank coolant temperature sensor. If the normal system fails to respond, the RH bank temperature sensor reaches a higher threshold and this causes the RH ECU to activate an emergency relay (relay A in the passenger footwell). The emergency relay sends power directly to the 2 fan relays (H & R). Since the fans do turn on (eventually), the relays themselves seem ok. I would suspect either the LH bank coolant temperature sensor or an HVAC issue. Since the LH bank temperature sensor doesn't talk to anything other than the HVAC ECU, it's not possible to get a temperature reading with an OBD2 scanner. However, you could, in theory, check the resistance of the LH bank temperature sensor at a connector in the passenger footwell. I believe pin 18 of the large plug shown at the bottom of Ryan's photo should be the LH temperature wire: Image Unavailable, Please Login Should be a grey wire on pin 18.
These are the fans I installed: Spal Electric Fans IX-30102113. Its been a while but I think they are the same part number as the stock fans but when comparing the two the new motors are a lot bigger. They fit in both the 550 and the 575 shroud.
I appreciate the praise and recognition. The electrical theory for this modification may be straightforward and not a new concept, but I disagree that it’s just a few parts cobbled together. At least in regard to my harness, it’s built and fitted for our cars (456 and 550) using quality and heavy duty components that are made for the demands of the fans with safe installation and reliable operation, and not looking like a homemade concoction. I would also recommend referring further discussion back to the original thread as well. https://www.ferrarichat.com/forum/threads/550-engine-cooling-improved.622609/
We ship worldwide via FedEx from our location in the USA. These are in stock, and available for immediate shipment.
The fan numbers I came up with were 30102049 which is 2024 CFM and maybe about the same current draw as the original, 30102113 as mentioned and what I using, and 30107328 which is maybe a newer version. Sealed and brushless. At 2450 CFM a little less flow than the 2113. It is also about twice the price and seems to be an exclusive for Speedway Motors. I decided not worth the difference and taking a chance.
It seems that the shipping and tax to the UK will take the cost of this kit to $400, so I might as well make my own harness us. I’d love to buy from Aerosurfer as it’s good to support each other on this forum, but the extra costs make this marginal. The UK number listed is not operational. I think that there are some diy threads on this mod around, but @scowman what was the spec for the ‘fat wire’ that you used please?
It was the biggest one I had lying around. Smaller than the starter cable. About 4x the stock one. I used a loop connector over the alternator and crimps with heat shrink. I used waterproof relay connectors.
