What is this cold start clacking noise?

[ChrisTBird]

The video makes it sound louder than it really is. Noise settles down but never completely goes away. In real life, when the car is warm, you barely hear it. But it is quite loud when cold. It's almost like the old lifter noise you'd get with a sluggish lifter, but this AJ motor is over head cam... so I wouldnt think the actuators would have that much play. But what do I know, thats why there's TBN! :)

[Brad]

I wonder if it's one of the accessories powered by the belt (A/C, Alternator, PS pump)

[4LOWBIRDS+7]

That is not like anything I have ever heard on any of mine. I would be worried.

[carntz]

Wild guess exhaust manifold has a crack?

[jerrym3]

Belt tensioners can make a cold weather noise, but they don't usually last that long. Once the oil circulates, the noise goes away.

My wife's LS usually makes a noise on really cold mornings, but hasn't done it so far this year. And, it's been cold.

Maybe it's worth googling "belt tensioner problems 3.9 Ford engines"

[CaptB737]

Chris, I have a very similar sound from my car also. Mine only happens after sitting for a few days and not running. As long as the car is started and run on a regular basis I don't notice a thing. Once the oil pressure comes up the sound subsides and goes away. Mine also is not as rhythmic as yours, mine sounds like a series of relays slamming closed and opening again. I have read that these 3.9 engines have plastic secondary timing chain tensioners that might be worn out. There is a youtube video on how to replace them but it's job best left to a service center. I'm hibernating for the winter so my problem will get looked at this spring

[Jimr]

My 1st guess would be a collapsed lifter. Buy an auto stethoscope and you can narrow in on the noise.

[ChrisTBird]

It was intermittent today, but as always, faded down as it warmed up.

I did a lot of searching. A strong candidate may be the secondary timing chain tensioner. But other causes could be the cold start oil bypass valve flapping, the "camshaft phaser" (not the photon tho), and a fuel injector which I dont feel is likely.

Then of course there are accessories, but I think it sounds like an engine sound.

I wonder how bad that plastic timing chain tensioner could get? Does it cause any damage or just get loud?

[Cards]

Cold start rattle is fairly diagnostic of timing chain/tensioner issues.

[ChrisTBird]

Cold start rattle is fairly diagnostic of timing chain/tensioner issues.

How long does it take to do any damage like that? And if its that, being that its intermittent (long period or no run, and cold weather) I'm wondering if that points to that infamous plastic secondary timing chain tensioner or....?

[Rondor]

How long does it take to do any damage like that? And if its that, being that its intermittent (long period or no run, and cold weather) I'm wondering if that points to that infamous plastic secondary timing chain tensioner or....?

That is a serious issue and sounds like a good possibility too. I would guess our cars have a belt but still think it may be the tensionor or related. The more I listened to it the more I think it is internal.

[007Cruiser]

I think you may have serious trouble brewing. Best to have it looked at immediately. If it’s a timing belt it could go south in an instant causing a much more expensive repair. I wouldn’t start it again. Have it towed to a shop you trust for diagnosis.

[ChrisTBird]

Thanks 007 but it's a chain not a belt (three chains actually). As far as I know, unlike timing belt, timing chains rarely fail completely.

The noise stays quiet except when car has sat for couple days, and it's very cold out.

I still want to identify the culprit, but feel ok using the car with this intermittent issue that doesnt happen every time, and always goes away in a minute after startup. Well at least it gets barely perceptible, which can help with finding it.

[Fuchsaudio]

I have had a similar noise that fades when the car warms up. I'm fairly sure it's a cracked manifold or possibly a manifold gasket. I remember my pop having this issue on a car and that's exactly what it was. As soon as the temp gets up to normal, it's gone with only the slightest bit of mechanical noise from the front of the car. I suspected a possible leak (the cats were changed and I think maybe a leak exists in the pipe or a joint), but the cold made it worse for sure. Performance seems fine...

I had the oil checked and changed and it was fine in level and mileage and it had zero affect on this sound. I had not planned to drive in winter, but have not yet lined up a lease for a winter car. The car runs fine otherwise. I suspect an exhaust leak because unless I close the vent for outside air entering the car I have a strong exhaust smell in the car. I'll report back when it hits a lift.

If I need an exhaust manifold, are there header options, should I want to consider ?