Bucketlist

I have a 2004 Lexus LS 430 with 143,000 miles. The last three or four times I started the car I noticed a ever so slight sensation of engine movement when starting it. What are the symptoms of a bad engine or transmission mount on this particular car?

Brewmyown

Pop the hood, put the car in drive, put your foot on the brake and give it a little gas then let off quickly. If the motor rises up and then back down, they are likely bad. You may even feel a thud when it comes back down. even new mounts will let the motor move up and down a bit but it should not be much at all. maybe 1/2" or so.

If you're not comfortable holding the brake and have a safe area to drive a few feet with your hood open, you can see the motor that way as well. put it in drive and hit the gas like taking off from a stop very quickly and let up. It only takes about 50 feet of space. An empty school parking lot works well.

Sometimes they are hard to see visually. One of mine was actually in two pieces but I couldn't see that until I went to remove it. I knew they were bad because I felt the thud when I jumped on it from a dead stop and let off the gas.

As far as the trans mount goes, its simple and quick to replace and odds are if any are bad (1 trans and 2 motor), change them all.

BradTank

On mine, you could feel it through the steering wheel and it seemed to get much worse when the AC was NOT running, the lower idle speed seemed to exacerbate it. So you might want to experiment turning the AC on and off to see if you can feel it that way. Even with motor mounts that needed replacement, the vibration wasn't awful, more like a normal economy car and I seemed to be worse than when I first bought it.

But I actually regret not swapping them out sooner, it was night and day how much smoother the car was after replacing them. It's hard to tell the car is even running. Mine is a 2004 and had around 150k miles.

It's all how **** you want to be, but the way the car was designed with fresh motor mounts, you're supposed to feel almost zero vibrations from the engine.

tradosauru

Sounds like a two person job. I don't know how you can inspect the motor mounts while you are pressing the gas and brake while in Drive.

Brewmyown

With the hood open you can see the motor from sitting in the drivers seat.

Bucketlist

Thanks for all of the replies. Should be an easy diagnosis.

tradosauru

You could see the top of the motor but not the motor mounts themselves. Really need another person with a flashlight on the motor mounts as this procedure is being performed.

ancdmd

No need to inspect them, just replace them since they're shot anyways. Mounts are a must for replacement well before the mileage you have on them.

Bucketlist

I had the engine and transmission mounts replaced. They were still intact. However, after being replaced with the car being 12 years old with 143,000 miles, what an unbelievable difference. Engine is now almost inperceptiple on startup and is quieter when idking and under power.

Thanks again for all the replies.

tradosauru

What brand of motor mounts did you install? OEM or some other brand?