[ibe98765]

The engine idles consistently at about 600 RPM. Tach is steady.

However, about 75% of the time, the idle FEELS rough. I can feel it in the steering wheel. It kind of feels like the car is idling at a higher number, like 1200, even though the tach continues to read 600. Another description might be that it feels like the engine is heavily modified. It "sounds" like it has a lot more power than it actually does if this makes any sense.

But some of the time, it will seem to settle down and be relatively smooth and quiet (for an engine with 106k miles on it).

I had a couple of mechanics look at it and both claim the motor mounts are shot. Neither put the car up on the lift. The first wanted about $1300 to replace all 4 mounts.

The second one tested the car on the road and then back at the garage, did a test with his assistant while I watched with the hood open where I could see the engine move significantly front and back as [I think] it was shifted in/out of gear. I was told this was confirmation of bad front/rear mounts. He wants $500-$600 to replace only the front/rear mounts if I purchase them.

I always like to purchase parts myself, so I said OK, I will purchase the mounts and pay this guy to do the install job for the replacement.

Now, when I sourced and purchased the front/rear mounts I saw that they have wires and a sensor. Which made me wonder if it might be possible that sensor might be bad or the wire disconnected and I don't actually need to replace the mounts?

How does the motor mount sensor in the front/rear mounts work? What does it do? What triggers it?

 

[amc49]

 

[ibe98765]

Thanks! Great video.

 

[amc49]

I too learned as much as you did.

 

[bldyfinger]

Replace the front mounts. Very easy go on you tube for information. Just don’t lift engine jacking the oil pan you will crack the seals.

 

[1.8TTony]

But some of the time, it will seem to settle down and be relatively smooth and quiet (for an engine with 106k miles on it).

I had a couple of mechanics look at it and both claim the motor mounts are shot. Neither put the car up on the lift. The first wanted about $1300 to replace all 4 mounts.

$1,300 to replace all four mounts is a good deal......don't forget to replace that 5th mount.....the torque mount. Up top, passenger side near the strut bearing plate.

When it comes to your vehicles rubber components, it doesn't matter that your car has low mileage as the rubber compounds have still aged with time. You have an old car.

Regarding both mechanics declaring the mounts being bad without either of them lifting the car up in the air.........this tells me the first mechanic MIGHT know what he's talking about, and after reading that the second mechanic confirmed what the first mechanic said, it makes me believe BOTH mechanics know what their talking about.

This also tells me they both have plenty of experience dealing with vehicles which have experienced failed engine / transmission mounts. It's not Rocket Science, but it takes an experienced mechanic to know the sound, the feel and knowledge of how a how a cars acting when suspected motor / transmission mount failure is present.

@ amc49........that's a great video you posted. However the guy in the video is mistaken when he claims that the motor mount (he's showing) has hydraulic fluid in it. The motor mount he's displaying does not infact have hydraulic fluid in it. It has an anvil plate which simply (electronically) compresses & decompresses the rubber insulation to minimize engine vibration frequencies.

Nissan mounts with hydraulic fluid didn't come out until the 2007 model year and these particular 2007 mounts are manipulated via engine vacuum, not via electrical current. I think the only company which had electrical AND hydraulic fluid mounts back then was Honda beginning in 1998.....and the Honda mount system was a simple and rudimentary system. Simple as in:.....of the mount breaks, it loses fluid, the mount "deflates" and a wire in the mount grounds out and turns on the CEL. Very Jurassic approach.

OP.....I think I read that you stated one mechanic wanted to charge $600 to replace JUST the rear mount.....this is....AGAIN.....a good deal.....that rear mount is the most involved to replace. The other three mounts??? Easy. The top torque mount, no problem. Just remove particular bolts and slap in new mounts......but that rear mount.....that rear mount is gonna eat up hours to replace because the steering rack needs to be dealt with and it ain't easy nor is it quick.