AAA says I need new Engine mounts. When I rev my engine moves slightly but nothing more than I would expect to see on any engine. I have 200k miles on my Maxima so I wouldn't be too surprised if I actually need new Engine mounts .

What truly is the risk of not getting new engine mounts and what are some things to look for so I know when I should get new engine mounts.

 

Your current mounts will be cracked or broken, and possibly fluid even leaking out. If they are worn they cause excess vibration, but not really do harm. It isn't like your engine or transmission is going to fly out of the engine bay.

It's really up to you if you truly want to change the mounts or not. A car with 200K probably does need new mounts if they have never been changed before.

 

They're most likely referring to the front and rear mounts that attach to the cradle under the engine.

When they start to get really bad there will be a noticeable thump when getting on and off the throttle.

There's no real risk to driving on them till they get worse. As they break down the thumping will get worse but the motor won't break loose or do anything dramatic like that.

200,000 is around the time they could be going. You have to be sure the rear one isn't getting oil on it from a leaky rear valve cover. If oil is getting on it the new one will die pretty quickly too. It that's the case, as it probably is at 200,000 miles, I'd fix the oil leak first.

 

they're probably done at 200k. if you're auto don't buy new auto mounts, get the manual ones

side note: i'm not sure how it is in your area but all the AAA service shops around here get terrible reviews for overpricing repairs and being generally incompetent. my wife had her car towed to one of these one day when her car didn't start. they replaced the battery first and then told her there was something else wrong with the security system that kept the car from starting. she had to tell them to push down on the clutch when turning the key, it fired right up. wtf

 

whats the deal with auto's again, get manual ES ones with no electronics?

there was something with electronics in these and a big difference between auto and manual....... on to researching i guess...

 

autos soften at low speed/idle and firm up when you get moving, supposed to reduce vibration when you're sitting still and improve comfort. it won't take you long in your research to find horror stories of the auto ones failing and taking the ecu with it. it's recommended to unplug the auto ones to avoid this, so might as well buy the cheaper manual version

i opted for some regular manual mounts when i replaced mine and vibration is minimal. i imagine this increases the more you try and stiffen the mount (ES, window weld, etc) but can't speak from personal experience

 

The auto mounts are hydraulic mounts that stiffen as RPMs increase. Don't quote me on this but I think they stiffen at 1,000 RPMs. There are reports that the auto mounts in a 5.5 gen can fry an ECU similar to the IACV problem in a 5th gen. Because of this some people will rev the engine to stiffen the mounts and then disconnect the harness so the mount is disconnected from the car's electrical system and remains permanently in it's stiffer state (that's what she said? ) Other's will just purchase solid manual mounts with no harness to connect.

The manual mounts work fine but are slightly smaller and require manual mount brackets to fit. If you purchase the ES bushings to replace auto mounts the same principle applies. I have read on this forum that the rear auto mount is same size as the manual but I cannot confirm this myself.

 

I have original motor mounts on my 1998 (242k miles) that are still working fine so wasn't sure if i should leave them alone, or do that disconnect thing?

 

Doesn't apply to 4th gens. Leave them as is if you don't have excessive vibration.

 

You have not told us whether your car has an AT or MT.

If your car has an AT, then the potential risk is large: Maximas with AT have "electronic" engine mounts. These mounts can fail and damage your ECU, leading to a slew of expensive repairs. You should replace them, or at least disconnect them, ASAP (explanation and reasons here: https://drive.google.com/file/d/0B6O...1fNlF5QjQ/view .

Once you take care of your electronic mounts (if you have any), then the only issue is excessive engine movement. Common sense applies here - if the engine moves too much, it will damage other parts and will cost you more in the long run.

 

i have not heard that this applies to the vq35 engine. I only thought that the vq30 had those issues of taking the ecu out along with a bad engine mount?????