Rattle driving after cold morning starts

[lexefx]

When I start my 04 in the morning, I let it warm up 2-3 minutes.

Under that 1st mile or so of driving, when I lift off the gas, but not all the way off (like a coast without being off the gas) I get an annoying rattling sound. Its rhythmic in correlation with the rpm/ tranny speed. If I lift all the way off the gas, the sound goes away. If I pop the car in neutral while driving and rev the motor, the sound is completely gone. It appears only when I am in drive. It's doesn't sound like a heat shield to me...

Once up to operating temperature the noise is gone. There is no vibration associated with the sound.

Any ideas to look at, or solutions besides get a garage and warm it up for 10 minutes?

[troyhyde]

Based on your description, sounds like driveline. CV joint?

Brake dust shield?

[vtl]

Upper/lower mount?

[lexefx]

I really appreciate your help guys.


Based on your description, sounds like driveline. CV joint?

I'll have to have it checked out. Is there a process I can get into to check the CV joint? Last time I was up close the boot was intact.



Upper/lower mount?

I have done the lower transmission mount (IPD). I am not sure to what your referring to as an upper mount? If you mean the upper engine mount, that has been done as well. Please let me know.

[lexefx]

I also noticed today that in that 1st mile, it will rattle under acceleration, it's worse the harder you step on it. This 1st mile btw is all under 40 mph.

[vtl]

I have done the lower transmission mount (IPD)
OE lower mount has a very soft rubber. On purpose, I would guess. Polyurethane transfers a lot of vibration, that should be assumed and agreed with when you decide to switch to poly bushings.

Personally I pulled out poly subframe bushing inserts by IPD, waste of money. Same thing with HD TCV, I didn't like jerky shifts at all.

[lexefx]

I have not done the subframe or lower motor mounts. No telltale CV click from full lock turn in D or R.

[lexefx]

Polyurethane transfers a lot of vibration, that should be assumed and agreed with when you decide to switch to poly bushings.

My glovebox still vibrates to remind me ;).

This sound is weird, no associated vibration that I can feel.

[vtl]

I have not done the subframe or lower motor mounts. No telltale CV click from full lock turn in D or R.
When you switch in D, engine rotates. Upper engine mount and transmission mount is what keeps it in place. With polyurethane bushings in those mounts you'll have more vibration transferred to subframe, that's assured.

[Antherzoll]

When you switch in D, engine rotates. Upper engine mount and transmission mount is what keeps it in place. With polyurethane bushings in those mounts you'll have more vibration transferred to subframe, that's assured.

What if your subframe is solid? :)
http://cdn.shopify.com/s/files/1/0260/2623/products/FWDAWDSubframeBushings_1024x1024.jpg?v=1421372150

I don't mind my poly bushings. The vibration got worse with colder weather, but only at idle, on throttle it is nice and smooth. In fact it feels more connected when accelerating or using GT mode. If you can get around the idle vibration they are just fine. My recent tune has bumped my idle RPM to ~750 which has severely reduced this harshness.

Can you make a recording of the sound? Where are you hearing it?

[troyhyde]

Could be a sticky belt tensioner, they can clack.

Is the sound coming from an upper or lower location? Can you feel it in the floorboard or steering?

[Astro14]

Sounds more like exhaust, either a manifold leak or flex joint. Metal expands as it warms up and leak goes away.

I would check engine mounts, if they've got over 80K on them they're likely gone, and the exhaust manifold. A shop will need to keep the car overnight to diagnose it properly.