2005 Engine Vibration - Toyota Corolla, Chevy Prizm (1998-2008)

Hi,

We got some bad news today on our 2005 Corolla LE with 79K on it. We noticed an engine vibration...around 2800rpm to 3200rpm. There has always been some roughness to the motor around that rpm but it seemed to be abit worse the past month. The dealer felt it too and thought it was the right engine mount which we changed today. That didnt really do it so they spent a while looking for the issue with scopes and other tools and believe its either piston slap or something with the rod/bearing. Of course our extended warrenty just ran out but the dealer said they can help take care alot of the cost. For now they are going to watch it and see how bad it gets.

I cant imagine the cost for this even with them helping abit(I'm betting it wont be alot)so I hope it stays okay for a while.

Anyone have similar issues? Or someone have this yet put on serious miles without any issues?

Thanks!

Sorry to hear about your dilemma - though piston slap and rod knock are unusual for Corollas, unless you know a specific time when the engine ran out of engine oil or ever overheated. Is this a general mechanic or Toyota shop mechanic?

Is it possible to get a sound clip of the noise? Piston slap and rob knock will have a very audible noise as well as vibration. Since the noise happens at only a certain RPM range, I'd rule out both rod knock and piston slap - as rod knock gets worse with increasing engine speed and piston slap usually is most noticeable right after starting up and at idle.

That RPM range, especially when the engine warms up, is the starting point for when VVT-i tends to vary the timing (overlap between the variable intake to the exhaust valves). The 9th gen Corollas (2003+) have much of their a powerband running from off-idle 1500RPM, to just before redline (6000RPM). Since most cruise speeds have the engine turning close to 3000RPMs, this is where the overlap between valves tends to increase (timing advances) and continue to increase to redline to reduce pumping losses and keep emissions in check. At idle and low engine speeds, timing is pulled to enhance a stable idle speed and reduce startup emissions.

I would see if there is an issue with the OCV or oil control valve the controls the VVT-i actuator. Could also be an issue with the DBW system not being fully calibrated, as this model year was the first year that they introduced the electronic throttle control.

Thanks for the reply Fish!

This was a Toyota dealer. Whatever is causing it they didnt think it was very bad at all and even thought it was the motor mount. After they saw it wasnt that they unhooked the motor from the mounts and hooked up something to do a sound test. Sorry but he was rattling off stuff so fast I cant remember all of it but they also heard noise at 1600rpm which they felt was the main belt pulley. They felt...but were not sure the 2800rpm issue...that it might be the slap or bearing. I agree with you...why would it occur at such a narrow rpm range?

The car has been very well maintained by them...oil changes before they really needed it...heck its never even seen red line. My wife feels the roughness was there a while back(which I thought might be the cam chain) and maybe its gotten abit worse. I seem to notice it more now than back then.

To try their fix has to be a very expensive repair and I cant afford to have them "shotgun" it....so I guess we'll just have to wait and see what happens.

Another common problem area is the serpentine belt tensioner - you might even be able to see the little "shock" on the end actually jump up and down. That has been known to cause a significant amount of vibration to be transmitted to the cabin. That would also be keyed to a narrow range band, so it could fit your scenario. There is an idler pulley that could go bad as well. Hard to verify without taking the serpentine belt off, unless the bearing is completely shot in the pulley (it will be leaking grease, does not track with the belt or wobbles as the engine is running).

The dealership mentioning piston slap or connecting rod - that sounds a bit extreme. The idler pulley is a $15 part vs cost to open up the engine. Serpentine belt tensioner varies from $75-$150, depending on where you get one. But I'm pretty sure the 2005 use a revised part compared to the earlier 9th gen Corollas (though I could be mistaken).

>>>Another common problem area is the serpentine belt tensioner<<<

I suggested that to them as there was TSB for that(I think)...I just said to remove the belt and run the motor and see. His reply was they did feel there was a vibration from that but at 1600rpm...not 2800rpm. He never told me how they came to that conclusion. I am willing to change those out to be sure but they balked at that idea saying no...its not causing the 2800rpm vibration.