Ok let me show you my test done today. The car is in the garage on jack stands with no wheels on. Engine completely cold, not ran since the last few days. Outside temp is 14 degrees C / 57 F, the hood is closed. The garage door is fully open. I have put a digital temp gauge in the engine compartment at the brake fluid reservoire and the display at the dash next to the door opening. I start the car when the clock is 1 PM. And put AC on. After a few minutes, the engine temp is starting to be normal and the fans start to run and I count the seconds of how long they are running. First 20-30 seconds for a few cycles at 1:08 PM. Then a few later, they run for two minutes and then from now on, they run continiously. This is the original fans from the car was new in 1999 with a new 575 fan shroud installed this summer. The engine room temp is climbing quite quickly. The engine is only idling. The engine is starting to overheat at 20-25 minutes after start up. (See clock) View attachment 2878483 Image Unavailable, Please Login
As you can see, the coolant temp and the engine compartment temp continue to rise slowly and just continues to rise and after 45 minutes, the coolant is definately too high for a car at idle. The temp in front of the car is now maybe 20-25 degrees C because the car warm up the air inside the garage even if the big door is fully open. I check and the air is clearly drawn into the grill evenly on both sides. Fans are working... Image Unavailable, Please Login Image Unavailable, Please Login
Next thing to do is to open the hood all the way up with the engine still running. At 1:45 PM. The the temp start slowly to go down... After a few minutes it stabilize at about 100 C / 210 F and the engine compartment air is going down too. I would prefer the car to be like all other cars I have had where it is normal that the fans goes on and off and the needle is around 90-95 degrees as a consequense of the fans moving air through the radiator. My 550 is not like that. The fans go continiously and it is more like the outside air temp that determine the amount of cooling I get. It is not at all good enough air flow through the radiator. But when driving it goes down like all other Italian cars I have had... Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Then stop the engine with the hood still up. Engine room temp goes down very fast to 43 C / 118 F. After 5 minutes, the engine coolant have risen about 10 degrees and is still very hot as the circulation of coolant stopped when the engine stopped and the exhaust manifolds which are warmer and the heat shields around them is about 250 degrees C / 480 F. Then when restarting the car, the needle goes down quite a lot. After this test I just let is be off to cool down. This shows clearly that the hood is very tight with no place for the heat to rise up. What I realized is that the heat goes out around the shockabsorbers and out the wheel wells. And a littlebit out the side vents, but not a lot. Image Unavailable, Please Login Image Unavailable, Please Login
Are there anyone here which could do a similar test for comparison? Preferrably one who have not changed the radiator. To make for an even comparison. I have done the following: 1) changed water pump a few years ago. No difference. 2) Run a cooling system cleaner. The coolant was perfectly clean. Not a single sign of dirt or rust or similar. The car seemed to be able to run longer before starting to overheat, but when I tested, the car had no undertray as it was just a few days before I got the new heat shroud. So either the heat dissipate more efficiently, or the cleaner actually worked. 3) 575 fan shroud installed. Helped quite a bit. It takes longer time before it is starting to be hot. 4) Radiator cleaned taken out of the car and cleaned two times very well. It was of course quite some dirt in there. Ferrari in Modena denied to take the radiator out to clean it even If I asked specifically for this. They said the radiator was clean because they had looked through it with a flash light from the back side. Which was just a lie as there was indeed quite some dust after twenty years and 135.000s.... Have also tried to go down on the antifreeze ratio and that seemed to work a little. Still far away from good enough cooling at idle. The car is impossible to get to overheat when driving on open roads. So my conclusion after reading about people who replace the radiator and see no difference is that my radiator is just fine. It is simply not air going through it. Last time when I did a similar test, I slowly sprayed water / mist from the garden hose onto the radiatorene then the temp whet down almost immediately.
Old thread, I know....but I can vouch for John +1 on the overheating issue. My '95 456 GT was stranded in San Diego, almost a hundred miles from my home in OC due to a coolant issue. I agree the issue may be maintenance. I had a hole in the radiator.
