02 Exp Timing chain rattle?

[dnj90]

If there is a problem with the infamous timing chain, does it do it all the time?Reason I ask is because the engine runs fine and quiet for about 20 mins.Than the rattle begins.I would think if there was a problem the sound would be there all the time.also,if I had the timing chains fixed how long do you think it would last?TyIa

 

[2000StreetRod]

V6 or V8?

I assume that you have the 4.0L SOHC V6 but the 4.6L SOHC V8 can also have timing chain rattle.

When the engine is cold the oil pressure is greater than when the engine has warmed up. A typical symptom for cassette guide failure is timing chain rattle at start up because the oil pressure is low so the spring/hydraulic cassette tensioners are not keeping the chain taught. When the chain is loose enough to contact a metal surface it is very noisy until there is oil between the chain and the metal surface. It sounds to me like marbles rattling around inside the engine or a diesel engine.

Your symptoms are different. When the engine is warmed up is the rattle noisier at idle when the oil pressure is low or is it noisier at mid engine speed? Have you eliminated an external source (such as bad water pump bearing) by running the engine for less than a minute with the serpentine belt removed after the engine has warmed up?

 

[dnj90]

Thanks for the response. It is the v6. The noise is more when the motor idles than when it is reved. Didn't know to take the belt off. I assume if the belt is off and it stops its somethimg different then the timing issue? If so,what would you think to look at next?

 

[2000StreetRod]

accessories

To prevent engine overheat don't run the engine without the belt for more than a minute. If there is no noise without the belt then some of the possibilities are:
water pump, power steering pump, A/C clutch bearing, alternator bearing, belt tensioner bearing, or belt idler pulley bearing.

If the noise is still present without the belt it could be from the harmonic balancer. Other possibilities are crankshaft rod and main bearings, excess valve lash from failed hydraulic lash adjusters, sticking valve, rattling catalytic converter heat shields. Maybe your oil pressure is low due to failing oil pump. Ford "cheaped out" with the simulated oil pressure gauge that is actually just an idiot light. It's driven by the oil pressure switch that activates/deactivates at about 5 psi. How many miles are on the odometer?

 

[dnj90]

There's 164k on it. By the symptoms I described do you think theres a chance it's not the timing chain's? Do you think its worth keeping or should I get rid of it? I picked it up for 575 at an auction.Thank you again for all your help.

 

[SideTrackTap]

There's 164k on it. By the symptoms I described do you think theres a chance it's not the timing chain's? Do you think its worth keeping or should I get rid of it? I picked it up for 575 at an auction.Thank you again for all your help.

I think your first step is diagnosis. You have to get an idea of where that noise is coming from. Removing the serpentine belt is fairly easy and can be done with basic tools. Then running the engine without it, very briefly (like StreetRod said, less than a minute), you may be able to identify and/or eliminate some of the options he has listed.

I did this on mine. Twice actually. I might advise you do it twice too, once when it is cold, and once when it is warm, since you said the rattle/noise doesn't surface until it's been running about 20 mins.

Chris

 

[nicmartim]

Mine is doing the exact same thing. Upon startup, it purrs nice as the day it was built. Let it get a little warmer and it starts clacking. Not harsh like some of the YouTube videos Ive seen but kind of like a sewing machine. Rhythmic but not a continuous sound. Clackity-clackity-clackity, etc, etc....

This morning I removed the accessory drive belt and ran it for a short bit and the noise persisted. I have it narrowed down to the left side/center. Does not sound like it is coming from the valve cover area, but up front which scares me most. Could it be the hydraulic over spring tensioner? Perhaps a plugged up oil passage in the tensioner could cause slack??

BTW, mine only has 133k on the 4.0 and has an oil change EVERY 4k since we got it w/ only 70k on it.

 

[BobRob]

Mine is doing the exact same thing. Upon startup, it purrs nice as the day it was built. Let it get a little warmer and it starts clacking. Not harsh like some of the YouTube videos Ive seen but kind of like a sewing machine. Rhythmic but not a continuous sound. Clackity-clackity-clackity, etc, etc....

This morning I removed the accessory drive belt and ran it for a short bit and the noise persisted. I have it narrowed down to the left side/center. Does not sound like it is coming from the valve cover area, but up front which scares me most. Could it be the hydraulic over spring tensioner? Perhaps a plugged up oil passage in the tensioner could cause slack??

BTW, mine only has 133k on the 4.0 and has an oil change EVERY 4k since we got it w/ only 70k on it.

Mine was very similar with the rattle most pronounced between 1800-2200 RPM while accelerating. After inspection, I ended up replacing the primary tensioner in the front. That was 10,000 miles ago at 137,000 or so and it's quiet as a church mouse.

Take the time to diagnose the problem first. Could save you a ton of $$$.