Warm Start-up Rattle/Grinding noise

Hello fellow members of the explorer community. I was curious if anyone could help me find a noise my 2004 Ford Explorer 4.0 SOHC vin K 4wd XLS 64,000 Miles Explorer started making about a week about. This noise sounds like a Grinding Rattle and occurs on start-up, however it seems to only occur on a warm start-up rather than a cold one. Some of the research I did made it sound like it could be the timing chain tensioners, except that noise seems to occur on a cold start-up. Perhaps it could be the starter going bad? Not sure how a hot/cold start-up would effect the starting making a noise or not though. Any help would be much appreciated! TIA

Timing chain rattle can happen when warm as well as cold.

But, without being able to hear the sound, I am going to guess that the starter Bendix drive is not releasing. That's fairly common. The fix is to replace the starter. It's a very distinctive sound if you know what you are listening for.

Some of these had trouble with cracked flexplates or loose torque converter bolts, but I think that was mostly older ones. In any case, confirm the problem before you start swapping parts.

Researched this alot , I have an 04 with 132K miles , got the part time "rattle" noise sometimes when id first start it up , positive that its my plastic tentioner cassettes for the timming chain , I switched to 5W30 full synthetic oil just afew days ago , hoping this will help out ..without "hearing " your noise id have to guess its your problem too , if it was the bendix in your starter it wouldnt be so much a rattle , as a noise of the starter not disengaging

rb142 said:

Timing chain rattle can happen when warm as well as cold.

But, without being able to hear the sound, I am going to guess that the starter Bendix drive is not releasing. That's fairly common. The fix is to replace the starter. It's a very distinctive sound if you know what you are listening for.

Some of these had trouble with cracked flexplates or loose torque converter bolts, but I think that was mostly older ones. In any case, confirm the problem before you start swapping parts.

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Okay thanks. I forgot to mention that it makes the exact same sound for a fraction of the second when you shut the engine off also, does that also point towards the same problem with the starter? Thanks again

jbwilson3791 said:

Okay thanks. I forgot to mention that it makes the exact same sound for a fraction of the second when you shut the engine off also, does that also point towards the same problem with the starter? Thanks again

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No.

WHERE exactly is the noise coming from? Front, back, high, low, etc.? Take off the belt to eliminate the accessory pulleys. Is it coming from the bell housing area? Narrow it down. Check the fan clutch too.

rb142 said:

No.

WHERE exactly is the noise coming from? Front, back, high, low, etc.? Take off the belt to eliminate the accessory pulleys. Is it coming from the bell housing area? Narrow it down. Check the fan clutch too.

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I took the belt off and it still made the noise. Since I was by myself tonight and the sound only last a few seconds it was hard to pinpoint the sound after starting it then rushing to the engine but from what I can tell it sounds like it's low in the engine and possibly center or towards driver side.thanks for your help btw

rb142 said:

No.

WHERE exactly is the noise coming from? Front, back, high, low, etc.? Take off the belt to eliminate the accessory pulleys. Is it coming from the bell housing area? Narrow it down. Check the fan clutch too.

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Found out it was a noise coming from the catalytic converter. It doesn't appear to be the heat shield that is rattling, does that mean the converter is ruined?

jbwilson3791 said:

Since I was by myself tonight and the sound only last a few seconds it was hard to pinpoint the sound after starting it then rushing to the engine

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Been there... trying to chase down that chain noise...

jbwilson3791 said:

Found out it was a noise coming from the catalytic converter. It doesn't appear to be the heat shield that is rattling, does that mean the converter is ruined?

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It could be a bad cat. Bang on the can and see if it rattles. Otherwise, you pretty much need to pull the cat off and see what's in there.

rb142 said:

It could be a bad cat. Bang on the can and see if it rattles. Otherwise, you pretty much need to pull the cat off and see what's in there.

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Okay I'll do that, and if need be it doesn't look too difficult to replace. Just pricey. I'm worried about throwing a code if I remove it to check it out though, is that likely?

No, you can't throw a code if you aren't running the engine while the cat is out. If the cat is melted down, you would probably have codes already, and it would be running very poorly. Maybe something else dropped in there. Did Iffy Lube pull it off to drop the trans pan? Are you sure the noise is inside the cat can? If you take it off, look inside. If it is full of black chunks, you need a cat. If the honeycomb looks ok and you don't have a catalyst efficiency code, it's probably fine.

rb142 said:

No, you can't throw a code if you aren't running the engine while the cat is out. If the cat is melted down, you would probably have codes already, and it would be running very poorly. Maybe something else dropped in there. Did Iffy Lube pull it off to drop the trans pan? Are you sure the noise is inside the cat can? If you take it off, look inside. If it is full of black chunks, you need a cat. If the honeycomb looks ok and you don't have a catalyst efficiency code, it's probably fine.

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I'm pretty sure it is the passenger side Cat, when I have someone else start it with me right there it definitely sounds like it couldn't be anything else. When jiffy lube did the trans flush they said all they did was go through the lines. Needless to say either way I won't be going back there. If it wasn't a closed system id have done it myself. I'll take the cat off today and see what I find, maybe something is rattling between the heat shield and catalytic converter.

Check carefully for a crack on a mounting bracket or something like that in the area that might create a similar noise. Bang on some stuff with a mallet and see where it comes from. Happy hunting.