rattling noise under acceleration

[lifespeed]

Recently I have been hearing a rattling sound around 3000 - 3500 RPM during acceleration. Throttle position does not seem to have a lot to do with it, but it is more likely to make the noise if the engine is accelerating quickly. This noise started recently, and did not coincide with the installation of the Lidio tune.

Trying to diagnose, I removed the Lidio 91 octane calibration and returned it to stock. Noise is still there. I will replace the idler and tensioner as I was already planning to renew these items, but I don't know if these are likely sources of the noise.

I am suspicious of the timing chain, guides and tensioner. Is there any good way to diagnose these before going through the major expense of replacement? I know some people are near 200K miles with original timing set. Yet there are others who have already replaced them and cured their problem. Despite evidence the 4.6L 4V is a pretty good design, I do not believe a timing chain that doesn't stretch, nor guides/tensioners that don't wear have been invented yet.

[slickster]

Can you raise the throttle from under the hood to check and see if its the belt tensioner which I think it might be as I had the same problem

[lifespeed]

Can you raise the throttle from under the hood to check and see if its the belt tensioner which I think it might be as I had the same problem

I will check this tonight.

[RF Overlord]

I do not believe a timing chain that doesn't stretch, nor guides/tensioners that don't wear have been invented yet.Mod motors are not known for timing chain issues, however the 2V guides have been known to wear through, especially in the 2000-2003 range, but this is usually in motors have have not been well-maintained.

Usually they show up as a sewing-machine noise at idle, not so much at mid RPM, although it is possible.

[lifespeed]

Mod motors are not known for timing chain issues, however the 2V guides have been known to wear through, especially in the 2000-2003 range, but this is usually in motors have have not been well-maintained.

Usually they show up as a sewing-machine noise at idle, not so much at mid RPM, although it is possible.

That is my understanding. Hopefully this is just a bad belt tensioner I can fix tonight.

[justbob]

You are positive it is not detonation you are hearing correct?


Self proclaimed Builder Of Badassery.

[fastblackmerc]

You are positive it is not detonation you are hearing correct?


Self proclaimed Builder Of Badassery.

Does it sound like marbles in a tin can?

[lifespeed]

The sound (was) more of a buzzing sound, like a timing chain whipping past an aluminum cover. Hard to describe sounds, I would have posted a video but the new belt, idler and tensioner has largely eliminated the noise as the engine runs through the RPM range.

However, there is still the tiniest bit of noise, harshness, or buzzing left as the engine revs. It seems to occur for a second, sometimes in the 3500 RPM range. Close to 6000 RPM I hear some unpleasant noise also. This motor shouldn't float the valves with 100K mile valve springs at 5800 RPM, should it? Of course I don't rev it like this daily, but expect it can handle it no problem.

The drastic improvement seen with the new serpentine parts leads me to believe there is another accessory that needs attention to cure the remaining noise. I understand our alternators have a clutch that disengages at full throttle? I would not hesitate to rebuild the alternator based on mileage alone, as brushes and bearings do wear. Water pump probably falls in the same category, I would replace it just because I don't want it to dictate the timetable with a leak during a road trip.

I would probably rather not shotgun-replace the power steering and AC if they don't need it.

Any ideas on narrowing down the accessory I am assuming is guilty?

[justbob]

The alt. has the same 6203 bearing front and back as all the idlers and tensioner.

I've replaced plenty of WP's on these wore out before they even saw 40,000 miles. Yours original?




Self proclaimed Builder Of Badassery.

[lifespeed]

I should probably replace the water pump and rebuild the alternator without giving it a second thought and be glad they made it this far. Normal maintenance at 101K miles. Everything on the motor is original except the ignition coils and spark plugs.

Why did you replace the water pumps, leaks or bad bearing? Do our alternators have a clutch that wears out also?

[lifespeed]

Here is an interesting link to the Litens Overrunning Alternator Decoupler (OAD). (http://www.decouplerpulley.com/index.cfm)They list applications for 2004 Panthers. Interesting addition is the torsional vibration damper, not just a One Way Clutch (OWC).

[justbob]

Why did you replace the water pumps, leaks or bad bearing? Do our alternators have a clutch that wears out also?

Both, stiff rotational spots, leaking, or both.

No clutch that I recall, only the pulley that's clutched.

You've done very good if everything is original.


Self proclaimed Builder Of Badassery.

[babbage]

ese items, but I don't know if these are likely sources of the noise.

I am suspicious of the timing chain, guides and tensioner. Is there any good way to diagnose these before going through the major expense of replacement?


Got a flexible camera/light deal to snake into the front cover area for a look/see?

[Ambitious1]

I know I am reviving an old thread, but I have just started experiencing a similar rattling, like a sewing machine noise when under acceleration on my higher miles MM. This seems to only occur when accelerating uphill or when merging onto the highway. No rattling at start-up and no noise at idle and no noise when cruising on the highway.

It seemed to be coming from under the right valve cover, so I went in and replaced all sixteen lifters on the right side. Drove it and the rattling is still there. Does anyone have any suggestions? I am now thinking timing chain tensioners or cylinder head? Thank you in advance.

[Turbov6Bryan]

Did you clean out the oil squirter for that side head? It bathes the stuffs in oil to keep the stuffs lubricated. Common to be plugged with oil pan gasket material from timing chain replacements..