Motor mounts

Three

How many miles on the odometer?
When were the iridium spark plugs last replaced?

Don't forget the basics before focusing upon an issue like motor mounts which is not a high failure rate item.

 

Considering the car has logged 237K miles, what do you expect. If the engine runs OK after the first second has elapsed, then why worry.

A failed motor mount is not going to change how the engine sounds. It will allow the engine to move around more than normal if the mount is loose, that is all.

 

Never seen motor mounts mentioned here in almost 8
Years. They don't fail because its tiny little motor
That runs rough and is very noisy with its solids.

 

Yeah....but tiny little 90 horse motor.

 

I don't think that would be particularly difficult. The official name is "engine moving control rod with bracket".

Tightening torque is 74 ft.-lb for the bolts that go into the powertrain and 41 ft.-lb for the bolts that go into the front suspension crossmember.

I would also suggest using a hydraulic floor jack with a piece of wood in the saddle to hold up the powertrain while you are replacing that part. It shouldn't be under much load since the top motor mounts are holding the engine, but just as a precaution.

 

Have someone watch the motor mount when you start the engine. You will see if it rocks at that point. Be sure to put wheel chocks in front of the tires first though. You could video the motor mounts too.

 

I recently changes two of my engine mounts (one underneath and one on the passenger side). The engine run a lot quieter. I initially did not understand why. But after some analysis, there are two reasons for engine noise improvement and make it runs smoother. First, Engine mount is designed to absorb vibration. Old engine mount cannot do a good job on this and therefore some of the noise that we hear (the typical Toyota valve noise) was actually from the engine mount. Second, replacing the mount make the engine run smoother because This Prius, the exhaust use donuts to connect between the exhaust manifold and the center pipe. Old mount may slight change the position of the engine inside the engine compartment. Replacing engine mount can correctly position the engine and therefore making the donuts connection perfectly align and reduce the exhaust leak. I believe some people may have experience that as the car get old, exhaust sound getting louder even after replacing the donuts and check that there is no leak. This is the reasoning. I recently refurbish my Prius front end by replacing the lower control arm, sway bar bushing, links, ball joints, and tie rod. And I found there there were still noise, took me some time to find out that it was the engine mount. After replacing the two engine mounts, the engine become much smoother. Still I need to figure out how to change the driver side engine mount. Basically, my car drive almost like brand new even it has over 190K miles.

 

Can you let me know which two your replaced? A diagram or pic would be great and also any instructions on how to?

I think my main culprit is the mount labeled "1" in the diagram.

 

Did you try replacing #1 on that diagram? My prius needs engine mounts too at 200k I can definately feel a lot of NVH through the body as the engine kicks in.

 

No. I am sitting at about your mileage. Am doing a refub on her. First going to change all the shock and mounts. Then will tackle the mounts of necessary .

.

 

Sorry for the late reply, 1 and 4 are what I replaced.

 

At some point I also want to replace "5" since replacing all engine mount will definitly made the engine smoother. I mean my car has almost 195K miles and it still run like new. why now? and the mount is not too expensive. The only issue is I don't know how to remove the inverter for the mount to install.

 

I replaced #1...it was a simple job of removing three bolts. The mount wasnt torn or anything. It didnt make a whole lot of difference in terms of play when the ICE starts and stops. But what I did notice was a different in the firmness and power delivery when gas pedal is pressed to get going. Especially on highway.

 

Did you ever get around to replacing mount #5? If so, what were your results?