First off I apologize for posting another questions about "rattling noise" but I couldn't find any other posts that were similar to my problem.

When starting my 2004 TL with auto trans, the car idles a little rough and when put in reverse a rattling noise starts that is as loud in the cabin as it is in the engine bay. In the engine bay the rattling noise sounds like it's coming from the intake area (top of engine). From in the cabin, it just sounds like it's from the engine or possibly close to firewall. This noise continues when in neutral.

However, it does not make any unusual noises once the car is put in drive.

Any ideas based on experience with this issue would be appreciated.

 

Cars are pretty weird when it comes to rattling, especially when you hear them from cabin. It could be coming from anywhere and may echo a little to make it sounds like it's from somewhere else.

First thing I'd do is make a video of it from cabin and from outside. Videos help understand the kind of sound (if it's metal on metal, metal on rubber, etc). Without a video, I don't think it will be easy to isolate the issue. Just my .02 cents.

 

What do you mean by idle a bit rough? Does it sound rough? Does the tach needle jump?

I highly suggest taking a video too.

 

The rough idle I was referring to is a shaking of the car. The tach needle does not move.

When the car is first started, the drivetrain seems to clunk, almost like a loose motor mount or transmission mount. I had a mechanic look at it and hes said the mounts were "on their way out" but not broken. I guess the hydraulics in the mounts are worn.

Once the car is put in reverse there is the rattling noise I mentioned. There are two videos attached with sound.



The rattling when put into reverse does not occur once the car is warmed up.

is it possible the mounts are pressurized by the engine and are not holding pressure while the engine has been off for a while.

Any input is welcome.

Thanks,