Rumbling Wheel Noise in 3-1/2 month old Prius

[smarano]

In the past week I've noticed a low rumbling sound emanating from what appears to be the right front wheel of my 3-1/2 month old 2006 Prius. It was subtle at first, but it appears to be getting more prominent and I can detect a slight vibration, more like a 'roughness' coming from the right wheel. It happens at all speeds, but is most discernible when the car is driving at low speed and it's running on electric only, and where there are ripples in the road (not potholes). Oddly, I don't hear any unusual knocking sounds when the car goes over a pothole.

I immediately thought that this might be a delayed reaction to a really bad incident with a huge pothole/ditch that I drove over in late November (see following post: http://priuschat.com/index.php?showtopic=26865&hl=).

I took it to a local mechanic and we roadtested it. He heard the noise and suggested that it might be a bad bearing or even a loose strut. He put it on the lift and could detect no apparent damage to the strut.

I'm going to bring it to my dealer this upcoming week, but I was wondering if anyone here has any suggestions on what this might be. Could it possibly be a bad ball joint? I'm thinking that it's too much of an oddity to have this kind of problem on such a new car and it NOT be related to the above incident.

[jayman]

If I had to bet, I'd bet on a bad wheel bearing. It's a sealed unit, like almost every car/truck these days is. Take a bad impact, or just have it bad from the factory, and it must be replaced.

My '04 left front went last summer at around 54,000km. I happened to power the driver window down as I entered the underground parking at my condo, and heard an odd scratching/grinding sound. It was the bearing and it was warranty.

You can also tell if it's a bearing by jacking up that wheel and trying to wiggle the hub, see if there is a lot of play.

[Charles Suitt]

<_< I'm inclined to agree with jayman... Sounds like a wheel bearing. I would pursue having it diagnosed and replaced without delay. If it were to seize up, you could have more damage to the spindle on which the bearing is mounted.

[galaxee]

third the wheel bearing idea. it's possible that it was related to that incident.

[Devil's Advocate]

Yep, Sounds like a bad wheel bearing.

I think you can replace this one yourself necause it comes in an assembly that you have to buy and install and is not a seperate bearing. The assembly is about $200!

I have the same problm in the front left, admittedly at 85,000, so not as unexpected. I will be replcing this unit soon, but to date it has not affected my MPG so I believe it is still acceptable, but not OK.

[smarano]

<div class='quotetop'>QUOTE(Devil's Advocate @ Jan 16 2007, 02:04 PM) [snapback]376371[/snapback]</div>

Yep, Sounds like a bad wheel bearing.

I think you can replace this one yourself necause it comes in an assembly that you have to buy and install and is not a seperate bearing. The assembly is about $200!

I have the same problm in the front left, admittedly at 85,000, so not as unexpected. I will be replcing this unit soon, but to date it has not affected my MPG so I believe it is still acceptable, but not OK.
[/b]

Thanks, everyone, for the very responsive and helpful advice. I'll let you know what happens.

[jayman]

<div class='quotetop'>QUOTE(Devil's Advocate @ Jan 16 2007, 02:04 PM) [snapback]376371[/snapback]</div>

I think you can replace this one yourself necause it comes in an assembly that you have to buy and install and is not a seperate bearing. The assembly is about $200![/b]

Well, usually you need a hydraulic shop press to press out the old hub and press in the new hub. Then you have to be very careful to preload the assembly properly with that nut you see on the end of the shaft. Too tight and it will glow red hot and destroy itself in short order, too loose and you could lose a wheel.

[smarano]

Well, I took the car to my dealer and it didn't turn out to my satisfaction.
The classic Murphy's Law outcome where the rumbling sound wasn't very
noticeable this morning. As result the service tech, who sat in front passenger's
seat as I drove car for him for about 10 minutes, stated he couldn't hear anything.
He said with only 3,500 miles on car there was 'plenty of time for problem to
show itself under warranty.' Hard to argue that they should replace a wheel
bearing assembly when there's no outward sign of damage, and tech claimed
he couldn't hear anything.

I spoke with service rep afterwards who was accomodating. He offered to
have me roadtest car again with the service manager. But - anticipating
same outcome - I told him that I'd give car a week or so to see if noise
became more noticeable.

This is a tough and frustrating one that I'm not sure how to properly handle.
Car probably appears OK to one not accustomed to driving it, yet I KNOW
there is a problem. It was FAR smoother before (smooth as silk) and it clearly is not now.
And I'm pretty sure that MPG is being slightly affected (don't get quite the same high
MPG on same roads as before).

Stevejm

[timh]

Steve (or anyone else who might know about this subject),
I have an '06 Prius, also with a low rumbling noise. I'm not really able to tell where it is coming from. Did you ever resolve this? Our started making the noise late last summer. Like you, it seems to have started up about the same time as our mileage dropped by about 10%. It is subtle, and a Toyota repair person said he couldn't hear it. But once you've driven it a while, you can't miss it.
Tim

[sbend]

<div class='quotetop'>QUOTE(timh @ Feb 9 2007, 01:00 PM) [snapback]387551[/snapback]</div>

Steve (or anyone else who might know about this subject),
I have an '06 Prius, also with a low rumbling noise. I'm not really able to tell where it is coming from. Did you ever resolve this? Our started making the noise late last summer. Like you, it seems to have started up about the same time as our mileage dropped by about 10%. It is subtle, and a Toyota repair person said he couldn't hear it. But once you've driven it a while, you can't miss it.
Tim
[/b]

My dealer is ordering a new right front strut this weekend for my 2006 Prius. In October I started hearing an intermittent "clacking" when I went over some dips or bumps. It was highly unpredictable and the size of the dip or bump wasn't related to when it would occur. It sounded as if something was whacking the inside of my glove compartment or dash board. As it's gotten colder, I've noticed, the noise happens more often; if it's been in a heated garage then it won't (which makes it a problem for the mechanic to work on and then test). I'm curious to see if this solves the problem. Has anyone else had such a noise in their Prius?
Chris