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red battery light and viscous fan roaring - related?
[QUOTE=camweed;1307779]Hey Ashes.... I think my D3 alternator has just let go, the red battery symbol warning lights comes up (weirdly intermittent), the viscous fan comes on and the gearbox plays funny buggers.
It did it 6 months ago and LR told me it was a battery and they wanted some crazy amount. End up getting a better, cheaper one from a wholesale contact and all seemed fixed.
Now the dramas are back, there are no diagnosis faults, but from playing around, we are pretty sure its the internal parts in the alternator. /QUOTE]
Today my alternator red light went on.
Yesterday the viscous fan started to "roar", or more correctly, when the engine is at idle, most often now I hear a roaring noise from the front somewhere which I assume is the viscous fan coupling acting up. Sometimes when the engine drops back to idle, the fan sounds about normal, but at the next traffic light, the fan will be making the loud noise again. engine idle seems a bit higher now, about a thousand rpm rather than 800 rpm or so and water temperature is not as stable, maybe from 185F to 200F rather than a fairly consistent 197F. The outside air temperature is about -4C or +25F, pretty warm for the end of January.
Now today, the red alternator light went on. I have a ScanGauge connected to the OBD port. For what it is worth, whatever voltage the ScanGauge displays dropped from its usual 13.9 volts range to 13.3 volts and has tended to stay there for the last 80 km of driving.
In other words, the alternator seems to be putting out some power as the Xenon projector Daytime Running Lights and tail lights appear strong; hi line radio and NAV appears to be working OK as well. If it was not for the ScanGauge voltage and red battery light, I would not know there was any sort of electrical problem. There are no bad news messages or bongs either.
I did a search re the viscous fan and found the above thread, hence the question, do I probably just have an alternator problem and the viscous fan roaring is just a sideshow, or do I have two problems, or is it something else?
To make the question more interesting, I just had a new alternator installed at the first of the week, (500 km ago). My previous alternator was I think working OK but I have 150,000 km on my 3 and I wanted a spare to cart about, so installing a new alternator seemed like a good idea. Now I wonder?
I also note that the alternator gets charge instructions from the Engine Control Module; also the viscous fan appears to have an electric clutch of sorts that also gets instructions from the ECM. I guess I am wondering if I may have an ECM problem rather than a fan or alternator concern.
