400i RUNS HOT,FAN PROBLEM????

I would certainly approach as with any car with this problem:

Is coolant level, condition OK?

Is cap and system holding pressure?

Does the thermostat operate and open at correct temp?

Does coolant flow through the radiator?

Do the fans operate if switch is bypassed?

With this old of a car, I would expect to pull the rad, clean or recore, fit new thermostat, fan switch, cap and coolant.

regards, Brian
www.autocarsports.com

 

Another thing that can cause a car to run hot is air in the cooling system. Try to purge it of all the air and see if that helps. Also run the cooling fans straight from the battery to see if it might be a relay.

 

They do run hot, particularly if sitting still!
Check the fans, there are 3 on euro spec cars. 2 come on when radiator switch at bottom of radiator triggers via relays in foowell. Rear one comes on when air con being used. Hope its not a head gasket!

 

If the fans do not come on at all, check the fan wiring , the fusebox at the fan circuit, the fan thermo switch in the bottom of the radiator and the fan relay as well as the wiring. If the fans do come on, check to be sure the radiator is not clogged up or the fans are not turning too slow. Slow fans can be caused by bad wiring, bad fusebox, bad fan or believe it or not, a bad alternator that does not produce enough amperage to run the fans at the correct rpm. You should also check the thermostat, although they rarely fail.

 

short the wires to the thermo switch on the radiator...double check, but if the switch is bad, the VW rabbit version should work...it does for other Ferraris of the same vintage. If the fans don't come on, then it may be wiring or bad motors (motors are not the most robust)