I got a 95 ls4. I notice when I start the car after it's been sitting for a few hours, the second the engine engages I hear and feel a noticable thump in the engine bay. It doesn't do it when the engine is warmed up, just on the first start after it's been sitting for a bit. Everything is stock, including all bushings and such. It's got 91,000 miles on it. Any ideas??????

 

I got the same problem on my 91 with 160K but it's a clunking noise instead of a thump and it happens only when the engine is cold. The noise is gone now after replacing the engine mounts.

tvd51

 

tvd51, thanks for your reply. I had a feeling the motor mounts were getting close. Before you replaced the mounts, did your car have a vibration under acceleration? Not heavy acceleration, but like when going up a hill and the engine needed to work a little harder to maintain speed? I've got one, and I think it's the mounts as well. But everytime I've had it checked out, the mechanics say they're fine?? Go figure...probably waiting for one to break so they can stick it to me with a higher repair bill. Lexus.....persuit of perfection leads to higher repair bills due to lack of business in the shop. I think the rubber part of the mounts is shot, and the metal brace that holds the mount is hitting the engine and frame. Oh well, there goes the egg-nooge fund for the year.

 

It didn't have noticeable vibration under accelaration, but the engine was noisy at 1300 and 1800 RPM between 1-2 and 2-3 shifts. Everything was a lot smoother and quieter after the mounts were replaced.

tvd51

 

that sounds like mine too. i think i need some new ball joints as well, got the standard popping noise coming from the steering. i'm betting that's where my vibration is coming from. have you ever had to replace the bushings yet? I hear they wear out around 100k.

 

I have a 95 ls400 with 101K miles on it. I noticed the same thump at start up near the passenger side of the engine ... this noise normally noticeable in the morning or when the car has not been driven for a day. I think it is the engine mount.... i recently replaced the transmission mount and it smooth a little bit but the thump at start up does not go away.

One local mechanic said that it maybe the engine mount that will need to be replaced. I was thinking of replacing the engine mount pretty soon. I am not sure if I have to replace both sides (cost $143 a piece at dealer and $75 to install by local mechanic)... since I only hear the noise on one side.

Thanks.

Mario 143

 

Mario143, save your money from the stealership. you can get it on line for much cheaper.....$93.88 per mount at

http://www.toyotaandlexusparts.com/

I got my trans mount there, was perfect. For the price of one at dealer, you can get both fronts here.

 

Problem Fixed: Just had the engine mounts replaced, fixed the thump, fixed the vibration, fixed the engine noise, fixed everything. Like new again. Can't wait to hit 110 mph soon. I got a country road that is flat, empty, and perfect for blowing out the cobwebs. Got noise? Got vibration? Get new engine mounts.