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View Full Version : Re: Advice Requested / Rattling Noise


Ambitious1
03-05-2018, 07:25 AM
I would like to ask everyone's advice. I have just started experiencing a rattling, like a sewing machine noise when under acceleration on my higher miles (170K) MM, coming from under the right valve cover towards the back of the engine.

This seems to only occur when accelerating uphill or when merging onto the highway. Doesn't seem to effect performance in any manner. No rattling at start-up, no noise at idle and no noise when cruising on the highway without pressing the accelerator. I have always religiously changed the oil and filter every 3,000 miles and always used 93 octane.

I went in and replaced all sixteen lifters on the right side. Drove it and no change. The rattling is still there under medium to hard acceleration just like before. Does anyone have any suggestions? I am now thinking timing chain tensioners or cylinder head? Thank you in advance.
Svashtar
03-05-2018, 12:15 PM
The only sound I’ve had like this in my ‘03 was consistent knocking at moderate acceleration while going uphill, but I would think the 93 Octane would rule that out, plus sounds like it’s happening all the time.




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Spectragod
03-05-2018, 01:06 PM
Bad knock sensor, sensor unplugged, bad fuel, could be a lot of things, if it only happens under load it would need datalogged


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Cosgrandmarquis
03-05-2018, 10:21 PM
Might be more of a valve tick?
justbob
03-06-2018, 05:23 AM
I just want to know who volunteered to ride in the engine bay going up a hill and merging onto a highway? 🤪

My guess is air/fuel related.


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Ambitious1
03-06-2018, 06:24 AM
I just want to know who volunteered to ride in the engine bay going up a hill and merging onto a highway? 🤪

My guess is air/fuel related.


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I could be mistaken, but it sounds very distinct and very obvious. The first time I heard it, I literally thought I had something rattling in the glove compartment. If you sit in the passenger seat, it sounds like it's directly in front of you. I am looking at any and all options.
Dragcity
03-06-2018, 11:18 AM
Could it be the spark plug rattling around under the cover?

Piece of piston or chunk of valve in combustion chamber?

A simple pre-ignition on the hottest of cylinders?

Something rattling around in the cat?

Sounds a lot like the pre-ignition thing, as it happens under load.