# 2005 Mercury Grand Marquis - Rattling Noise **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [August 22, 2019, 4:49pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274 "2019-08-22T16:49:00Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 22, 2019, 4:49pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/1 "2019-08-22T16:49:01Z")
I have a 2005 Mercury Grand Marquis. It has developed a metallic rattle sound that is loud at idle and while running at the same speed. It goes away when I accelerate. I checked the oil and it looks good. The noise started off quiet so I ignored it. Now it is quite noisy. The rattle sounds like a stone rolling around in a steel drum. ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [August 22, 2019, 5:35pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/2 "2019-08-22T17:35:55Z")
My GUESS should be a heat shield. ---
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 22, 2019, 5:40pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/3 "2019-08-22T17:40:45Z")
I suppose I could go underneath of the car and see whether that is the issue, correct? ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [August 22, 2019, 6:04pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/4 "2019-08-22T18:04:35Z")
Yes, you could and should if you want to find the problem. You didn’t tell us the # of miles that are on the car. It could very well be a timing chain rattling. If it is, it won’t rattle long… it will go BANG and the engine will become a door-stop. Have a pro check the car over. ---
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 22, 2019, 6:12pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/5 "2019-08-22T18:12:47Z")
I dont need a door stop! 112,000 miles. I am going to check underneath tomorrow and will follow up. Will a timing chain sound like a stone in a can? Is that an inexpensive fix if it is a timing chain issue? I just got the car! ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [August 22, 2019, 6:17pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/6 "2019-08-22T18:17:04Z")
> [@Todd58](#): > > Is that an inexpensive fix if it is a timing chain issue No…………………… ---
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 23, 2019, 6:29pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/7 "2019-08-23T18:29:18Z")
I looked under the car and it sounds like it is coming from the part of the exhaust system that connects to the motor. Not in the rear of the vehicle but under like the passenger seat. Any thoughts? ---
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 23, 2019, 6:32pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/8 "2019-08-23T18:32:11Z")
Nothing loose under vehicle. I do not think the noise is coming from the engine area. Sounds like it is coming from what i described above ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [August 23, 2019, 7:31pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/9 "2019-08-23T19:31:16Z")
Maybe a broken flex plate. That is essentially the flywheel passing engine torque to the trsnsmission. As I said before; Have a pro check the car over. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [August 23, 2019, 10:57pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/10 "2019-08-23T22:57:55Z")
Could be any number of things, but the most common source for a rattle like that – at least from the posts we get here – is the heat shield above the catalytic converter. Suggest to double check that first. A length of old garden hose can sometimes be used as a stethoscope to narrow down the location of noises. ---
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 23, 2019, 11:08pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/11 "2019-08-23T23:08:47Z")
Here is what it sounds like. Taken from passenger side front ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [August 23, 2019, 11:11pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/12 "2019-08-23T23:11:51Z")
Holy smokes! Is the Check Engine light on? Tester ---
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 23, 2019, 11:19pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/13 "2019-08-23T23:19:15Z")
No lights on. Like I said earlier, that sound all but goes away with acceleration. At idle or a steady speed it sounds like that. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [August 23, 2019, 11:27pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/14 "2019-08-23T23:27:19Z")
Okay. I just let the son listen to the video. When the engine is cold, take rubber mallet and bang the catalytic converter. If it rattles, that’s where the noise is coming from. Tester ---
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 23, 2019, 11:40pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/15 "2019-08-23T23:40:34Z")
Thank you for your time. I will put it up on jacks tomorrow and give that a try and post results here. ---
**Author:** ![Scrapyard-John](https://avatars.discourse-cdn.com/v4/letter/s/f6c823/32.png) [@Scrapyard-John](https://community.cartalk.com/u/Scrapyard-John)\ **Post date:** [August 24, 2019, 3:15am UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/16 "2019-08-24T03:15:42Z")
Like tester said, check the cat converter(s). It sounds like the material inside it has broken loose and is rattling around. I think that car has 4 small catalytic converters, but I may be mistaken. ---
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 24, 2019, 6:25pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/17 "2019-08-24T18:25:35Z")
Drivers side cat ---
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 24, 2019, 6:26pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/18 "2019-08-24T18:26:34Z")
![file-78](https://global.discourse-cdn.com/cartalk/original/3X/e/6/e654d24ce4851985b8c8ab70a5ad0144d495bde1.jpeg) Drivers side cat ---
**Author:** ![Todd58](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/todd58/32/17237_2.png) [@Todd58](https://community.cartalk.com/u/Todd58)\ **Post date:** [August 24, 2019, 6:29pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/19 "2019-08-24T18:29:36Z")
Now it wont let me post video links! ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [August 24, 2019, 7:51pm UTC](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274/20 "2019-08-24T19:51:57Z")
Try banging on the pre-cat. Tester [Next page](https://community.cartalk.com/t/2005-mercury-grand-marquis-rattling-noise/147274.md?page=2)