Hi all, I appreciate this forum is Mopar performance orientated, but felt given the help I have received here it was right to give some feedback on the Mercedes fan modification.
So after a shedload of testing the fan and Dave Brown's controller in the kitchen, this along with my modifications of adding a timer and LED driver circuit, I eventually got the lot installed in my Land Cruiser........and it rocks!
At idle in our present 34°C heat, the fans initial speed is all that is needed to keep the Toyota cast iron 4.2 straight six cool. The fan blade pitch and motor speed even at it's lowest speed is sufficient to pull the temperature down enough to switch off, the engine is completely stock and the fan is not audible when running on slow speed with the bonnet open.
As there is no current test certificate on the car, I decided to do some off road work up some mountainous areas in the campo, these are accessible from where I live without getting caught on the tarmac. One of the hardest jobs for off road and expedition vehicle engines are high climbs with a heavy payload in low gears at very slow speed, and of course the high temperatures.
So during a long slow climb I watched the controller LED change colour from green to barely orange, and that was it. To clarify for those not using Dave's v3 controller, if I switch on the AC, this forces the controller to bring the fan up to 50% speed, and the controller LED to full orange, so I guess my test brought the fan to around 35 to 40% of it's maximum speed? During an even longer hard climb (rocks, troughs and gravel up to around 700 metres), the LED changed between solid green and again just short of full orange as the fan speed fluctuated up and down, as soon as I stopped, the fan came down to solid green, my coolant sensor is in the bottom hose, so responds to the effect of the fan almost immediately, despite the under bonnet heat and idling engine the fan was off in under a minute, and back to slow speed a few minutes later excellent!
Problems noted.
By intentionaly pulling the plug off the coolant sensor, I tripped the controller failsafe which brings the fan to full speed, at full speed there is a vibration/noise from the fan. Because of the commotion of wind noise surrounding one of these fans at full tilt it us difficult to pin point, I think it is more noise than vibration, and as I can see balance weights on the blades and none appear to have moved, it is possible I have either distorted the shroud so the blades are touching the frame, or perhaps distorted something during install?
Further investigation will follow when I have some spare time, no noise or vibration at 50% speed....odd?
The other issue is the 50 amp circuit breaker tripped after around four minutes. During 'kitchen' testing I do not recall seeing more than 47 amps however, this is an old breaker that had never been used, I might just be a little too close to the breaker limit or perhaps I have an 'aged' fan motor? Nothing is getting hot i.e. cables or fan motor so I will order a 60 amp version which should put that to bed.
There will of course be further testing in August when the temperatures will be 40-45°C if not more, if there are any issues or not I will update accordingly.
