Hey everyone.
Recently I noticed that my R50 starts to turn on the radiator fans more often than it used to but few days ago it turned into more troubling sound.
There is a loud buzzing when the car is hot, i.e. stop and go traffic with very little air flow or if I was to arrive home and idle in the drive way for 5 minutes. It's not a regular fan sound as those are on and make their regular sound.
Basically the sound is audible with the hood open but it's much louder inside the car.
Also, if I move the steering wheel from side to side it subsides for a second with the steering wheel movement but then starts again.
If it was the PS pump why would it be dependent on the engine temp/air flow?

Any ideas?

I will try to diagnose over the weekend with the car on jack stands.

 

Have you ruled out the little power steering cooling fan? Try unplugging it and letting the car idle in the driveway, while sitting in the car and letting the radiator fan come on and off a couple of times. If your noise is gone, it was that fan. I recently had a sort of similar noise (more of a rumbling, maybe) and a new PS fan cured it. It had me stumped for a while since it was way louder in the cabin than outside, and wasn't always present. I think that while the PS fan is small, the way it's mounted can carry a lot of vibration into the cabin when it start to go bad.

 

Does sound like the extra noise is likly the ps fan...
Bearings in it go bad from dirt/dust/sand/water.....
sound is likly telling you to replace the fan before ir seizes...
When it seizes, pre2005 my cars often blow a fuse, that will also disable the radiator fan....many cars were modified by the dealer, but often only when requested, or if a issue occured underwarrenty. On modified cars, a seperate fuse (shared with the optional backup sensor) will blow.....and the ps pump will just run hot....a possible $600+ fix. New ps fans are about $180-200.

 

I'm not sure if i'm convinced that this is PS fan.
What doesn't fit is that it only happens if the car approaches hot temp, requiring radiator fans to kick in. yesterday for example I left work and hit a standstill a mile away from work and was pretty much stationary for good 20 minutes. The noise kicked in after about 15 minutes of standing in traffic. The fans on radiator have not kicked in. As soon as I started moving for a minute or two at more than 20mph the noise went away and did not appear anymore on the rest of my 45min commute home despite regular stops at stop lights.
had I gotten home and waited in the driveway for 10 minutes, it would have surely come back.

 

Keep in mind that the radiator fan has two speeds, while the PS fan has only one. The PS fan come on when the low speed radiator fan comes on (and stays on if it switches to hi), so you'll only hear it when the engine is hot. When you first get stuck in traffic, only low speed radiator and PS fan will come on, usually just for short periods unless the ambient temp is quite high. The low speed radiator fan is pretty quiet and hard to hear from inside the car, so you may not know it's on but be hearing the PS fan rumble. I know it sounds strange since the PS fan is so much smaller, but this is what I experienced - from inside the cabin, the failing PS noise was far louder than the radiator fan.

 

you guys were right.
I was able to reproduce this over the weekend with car on stands. When the engine gets hot the radiator fan kicks in on low speed with PS fan not spinning yet. When the engine temp gets even higher the radiator fans kick in to the high setting also activating PS fan which does not sound bad from the outside/underneath the car but resonates inside the cabin with this buzzing sound.

In the process of diagnosing this i also found that I have the thermostat gasket leak with coolant sprayed all over the back of the engine, axle, and everything else there. I suspect that perhaps this dripping coolant was soaking PS fan and perhaps washed our the lubrication from the fan's bearing and hence the vibration. I will first attempt to re-lube the fan to see if it helps. If anything I'll have to replace the fan, maybe after the winter as it doesn't seem to be turning on much during my regular commute and now with colder months ahead it will not be coming on at all