MysteryFan

Hello,

I'm a recent Lexus owner of an LS400. I bought it last year in 2010.

Such a great car and I love driving it for the great ride but I've run into a problem.

My father has one as well his is 1998 while mine is 1999. He has 120k while I have 154k miles on our cars

The problem is that when I hear his engine... Well I really don't hear it at all, it is virtually silent. I've noticed this on other models of the LS as well. Mine however is loud and the engine vibrates when I accelerate and it also vibrates when I release the accelerator.

I would assume that my exhaust could be loose so that the engine or something is making it loud and vibrate.

I also recently replaced the transmission mount before this winter so that is fairly new. I as well changed the spark plugs and air filter as well as the pcv valve for the engine.

If anyone has any ideas that would be great!

silos5

iTrader: (3)

I suggest engine mounts are old.

JBrady

Noise and rough engine operation are NOT normal and need to be solved.
As noted the engine mounts are certainly worn out and should be replaced but that may or may not be the only problem here. If the engine is truly not smooth I would be looking at fuel and ignition, injectors and coils. You have 8 of each.

Check to see if the problem is engine or possibly driveline. Does it vibrate when cruising at a steady speed?

Additionally I had the accessory drive tensioner bearing fail causing noise and MUST be replaced ASAP. You can also get noise from a failing water pump (FIX ASAP) and or failing timing belt tensioner and idler bearings (FIX ASAP). Were those changed with the timing belt? The belt was changed... RIGHT?

As you stated you could also have something loose in the exhaust and or catalyst(s).

MysteryFan

Thank you for the thoughts on what my problem could be. I will try to see what the problem is based on what you guys have told me. But to help get further ideas I am posting a link of my engine being recorded from my phone.

Generic picture of a Lexus if anyone wanted to know.

http://www.youtube.com/watch?v=5XwDFmqcm8U

bornpeace

Replace engine and transmission mounts. the other way to know they are bad is you fill more kick on the second gear shift when the car is cold, mostly in the morning.

MysteryFan

Once again thank you for all the suggestions. I brought it into the dealer for them to take a look for me since I couldn't find it myself. It seems that the Y pipe has gone bad and is making the noise.

I hope that will be the end of this problem and hope that due to the Y pipe damage down below near the converters that those are also found to be damaged after the replacement.

Est cost to replace is around $1100. Ouch. I thought these are made of stainless steel?

Imperium11

common misconception stainless is stain LESS not stainproof it still corrodes just alot slower, 1100 is terrible even for a stealership do it yourself

the part is 400 bucks on ebay and some rusty bolts

this turtorial wont be exactly the same but should be similar
http://www.lexls.com/tutorials/exhaust/fpipe.html

bornpeace

Okay, the Y-pipe will make noise but not vibration. So while ur replacing the Y-pipe check transmission mount, check at the picture below,
the mounts after time be compressed down. When that happen transmission goes down too, close to 1 inch, with transmission down the Y-pipe will go down with it because they are connected together with a bracket in front of the pan. If the engine mounts are at the original position, the Y-pipe will be pushed down and cause it to make noise. Just a visual check may not tell the truth until you take the mounts out and they come in two peaces. https://www.clublexus.com/forums/ls4...placement.html

silos5

iTrader: (3)

+1 for trany mounts.
I just replaced mine: it was compressed and broken into 2 pieces:

smokincigs

My 1998 vibrates also but my last 1998 was smooth as silk and the previous owner changed both engine mounts and transmission mount. I need to do this to my current 1998.

bornpeace

those new mounts look messed up, the bolt are not straight. where did you get them?

MysteryFan

Don't worry I forgot to mention that I changed the engine mounts too already. So both trans and engine mounts are good. I'm hoping to replace the Y pipe this weekend at my local repair shop since they can do it for $600 with everything since I don't have the time or tools to get under the car right now.

Hopefully the Y pipe will fix most of the problems since it was corroded completely through.

silos5

iTrader: (3)

yes, they are not straight on the picture, and I got sccared when I first noticed it. But they actualy move and there is no problem at all inslalling them (I´m 100% sure OEMs move the same way, cuz theres a free movement in the center of the mount). I got them from ebay.