Roaring at 2,000 RPM...


rvaccare
07-07-2005, 01:50 PM
This is a big concern of mine, and hopefully, I am overreacting. About 5,000 miles ago ('99 Rodeo LS, V6, 3.2, AT, 4WD, 106K miles) I started hearing what can best be described as a loud, unusual roaring (this may also be what some refer to as a "diesel" sound) at EXACTLY 2,000 RPM, regardless of speed and gear. At 1,900 RPM, the roaring is not present, at 2,100, the roaring is not present - only at 2,000 RPM! I have been trying to determine what could be the cause, and I am close to taking it to a mechanic to have it looked at, but if at all possible, I would like to know if this is something minor that I could take care of myself, whether it requires a part, maintenance, etc., and if not, I at least want to know the possible problems when I do take it to a dealer. (Sorry for the run-on sentence - take a breath now) I am not really a gearhead. I am very mechanically inclined, but have never really learned much about cars beyond changing my own oil, tires, spark plugs, etc. Any help, suggestions, etc., are greatly appreciated.

rodeo02
07-07-2005, 02:06 PM
Could be the radiator/engine cooling fan. The clutches on these are supposed to allow the fan to slow down/slip at higher RPM's. There is a silicone oil and some type of temperature and RPM sensative valving that 'controlls' the fan. A bad clutch fan will make a roaring noise on every takeoff. Cold or warm.
G/luck
Joel

anthonyn
07-07-2005, 02:12 PM
First See if you can duplicate the problem while the car is in PARK. If this is the case, I suspect it is one of the drive belt driven components like power steering pump, alternator etc. Also, check the fan which can make a noise if the bearings are failing. Get a mechanics stethoscope and try to pinpoint the noise. My power steering pump use to give off a humming at around 2200 rpm. The hum would go away above or below this rpm. Replaced the pump and noise is gone

rvaccare
07-07-2005, 03:28 PM
These are things I hadn't considered. I have been meaning to ramp it up while in PARK to see if it happens, but for some stupid reason, I have not done so. Probably because I am always in such a hurry leaving the house every morning and work every afternoon. :biggrin: I will make a point to do this tonight and check back in tonight or tomorrow. Either way, if either of you are correct, it doesn't sound like anything serious, which is what I was fearing most.

rvaccare
07-08-2005, 08:53 AM
Okay, so I tried to replicate the noise while the car was in PARK, and no luck. No loud roaring/humming noise at 2,000 RPMs. In fact, it sounded rather smooth. So, where does this leave me?

amigo-2k
07-08-2005, 11:03 AM
how about an out of balance drive shaft? maybe it tossed a weight?

rvaccare
07-08-2005, 01:59 PM
how about an out of balance drive shaft? maybe it tossed a weight?

That could be. Not that I know much about the operations of a vehicle, but my impression is that it is something with the transmission, drive train, etc. I hope not, but you may be right. I had an incident last year where the car was shifting really rough after a young kid moved the gearshift into first gear (vehicle was not running of course) while installing a CD player. Somehow it straightened itself out on its own, and I had someone look at the transmission the next day and they said everything was fine. Another thing is that I have had problems with the 4WD not disengaging when I turn it off. Naturally, I don't use 4WD but a couple of times in the winter, so I don't know if it could be part of the problem. The 4WD eventually turns off, sometimes many miles later, but it rarely ever turns off as soon as I hit the SOTF button to turn it off.

anthonyn
07-08-2005, 09:33 PM
Have you had the bearings repacked before. My dad's corolla had a roaring noise that a bunch of mechanics could not diagnose. Eventually found it to be bad bearings.

rvaccare
07-10-2005, 03:58 PM
Have you had the bearings repacked before. My dad's corolla had a roaring noise that a bunch of mechanics could not diagnose. Eventually found it to be bad bearings.

Yes, in fact, they have been repacked twice. I didn't notice a roaring before when the bearings needed to be repacked.

Fluvannahoo
07-18-2005, 01:28 PM
I'm hearing what I think is the same noise in our 2002 Rodeo V-6. it is certainly noticeable in the lower gears with the windows down but seems to go away at highway speeds. How does one diagnose an ailing fan clutch? Is that covered under the 100k mile warranty?

Fluvannahoo
08-27-2005, 10:21 AM
This is a big concern of mine, and hopefully, I am overreacting. About 5,000 miles ago ('99 Rodeo LS, V6, 3.2, AT, 4WD, 106K miles) I started hearing what can best be described as a loud, unusual roaring (this may also be what some refer to as a "diesel" sound) at EXACTLY 2,000 RPM, regardless of speed and gear. At 1,900 RPM, the roaring is not present, at 2,100, the roaring is not present - only at 2,000 RPM! I have been trying to determine what could be the cause, and I am close to taking it to a mechanic to have it looked at, but if at all possible, I would like to know if this is something minor that I could take care of myself, whether it requires a part, maintenance, etc., and if not, I at least want to know the possible problems when I do take it to a dealer. (Sorry for the run-on sentence - take a breath now) I am not really a gearhead. I am very mechanically inclined, but have never really learned much about cars beyond changing my own oil, tires, spark plugs, etc. Any help, suggestions, etc., are greatly appreciated.
The roaoring in our 2002 became worse and then stopped, then started again at odd times. Anyway it is the fan clutch gone bad. I got replacement parts byt am unable to get the old fan off. There are 4 studs on which it is mounted and since the fan turns counterclockwise I assume they are LH threads. Anyway I can't budge the nuts that hold them on so I'm living with the roaoring sound until I can get some help.

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