Increasing engine noise/vibration/drone at higher RPM/accelertion 2011 versus 2014

Well Prii have always been a little "loud" under acceleration due to the CVT and small engine and minimal sound proofing, BUT

We have 2 Priuses (Prii??), a 2011 with 41000 miles and a 2014 with 7k miles.

My daughter got the 2011 to take to college. 1200 mile round trip so it made sense.

She maintains that for sometime, the 2011 is making more of the droning/roaring sound that a Prius makes when accelerating briskly. I did not really believe, her, but over holiday break, I had the opportunity to drive both cars more, and she is right.

The 2011 is clearly louder under acceleration. It also will develop a bit of a vibration at certain RPMs, even at very low RPM sometimes, when the economy bar is just beyond the electric mode.

The noise differential between 2011 and 2014 is most apparent at cold temperatures, but it does not resolve completely even with both engines fully warmed up.

This is NOT the cold startup rattle that is referenced in TSB 0012-10. I had that happen as well, and took it to a dealer, only to find out that the TSB 0012-10 has been withdrawn. Interestingly, they did find cylinder 1 misfire codes, though no CEL was showing. They could not reproduce, and sent me packing after extracting $99 from my wallet.

However, at the dealer, they were showing me other TSBs, and there was one about increased engine noise. It recommended replacement of an engine mount. But I cannot find that TSB anywhere on the internet.

Anyhow, does anyone know if this sort of noise increase is really the motor mount? Will something be damaged if we just live with it for now (daughter needs to leave for college)....

Other ideas? I am pretty handy and I could get under the vehicle and drop the bottom shroud, and start it up on jacks and see if I can locate a source. But it seems to do it worse when under a load -- just reving it up does not result in the same degree of "loud"..... And its cold and wet under there right now.....

Ideas? Opinions?

 

Wow, 147 view and zero replies. Must mean I either have a rare problem or I described it wrong.

In light of a couple other posts. I am bumping. I did find the TSB I alluded to. Pretty much describes my 2011 vehicle behavior. I need to check with a Toyo dealer to see if its a covered issue. Regardless, I think an upgraded motor mount is in order. Might cost some $$$ as I think its not a "drive train" warranty issue.....