Name that Noise (engine related)

[bhuff30]

I've noticed a bit of a tapping noise in my car when the engine is warming up. It is definately RPM related, and sounds a bit like a tapping lifter, but not such a clear tap. It is almost more like a slapping or rubbing type sound. What kind of sound does a worn chain guide make? It is most noticible when the engine is cold and at low rpms, like 1000-1800 rpm. It goes away when the engine is warm.

I've heard rod knock and piston slap, and it doesn't sound like either of these. It also isn't related to the clutch, TOB or pilot bearing.

Sound like a chain guide? Do the chain guides on the NPI engine have a tendency to wear? I've read that some 4.6s like to wear the chain guides badly, but don't know which years/models.

 

[wmburns]

How many miles? Yes the chain guides can wear. I would also think they could make a slapping sound.

I have an engine in my garage right now with a broken timing set (2000 Mustang GT Windsor 145K miles). The plastic on the tensioners wore down to the metal. Then there was metal to metal which quickly wore the tensioners all the way through. Then the adjuster piston directly contacted the chain.

After this, the surface area of the tensioner was drastically reduced. The slack in the chain was not well controlled. The chain slapping around broke the plastic guides.

Several small pieces of plastic clogged the oil pick up screen cutting off the flow of oil.

A large piece of plastic wedged between the timing chain and crankshaft gear siezing the motor solid.

If the sound is coming from the front of the motor, try removing a valve cover. This should afford enough access to inspect the amount of plastic remaining on the tensioners. Try to see how far the adjusting prawl is sticking out. There is only so much adjustment to be had.

Suggest buying an oil filter cutter. Cut the oil filter open and look for bits of metal. Also, the ground up plastic may leave a waxy residue in the filter element.

Note, the motor in my garage did not belong to me at the time of failure. The prior owner reported the motor siezed at a red light with no warning what so ever. I would have expected the timing chains to make noise before they failed. If the PO is to believe, this is not always the case.

Bottom line, a timing set is much cheaper than a whole motor.

 

[bhuff30]

The engine has 168k miles. The noise is much more noticible these days, but again, after the engine warms up it goes away. I guess I'd better open her up this weekend if I can.

 

[twogts4us]

I've got the same on my DOHC -and I came to the same conclusion - chain guides. I'm not so sure it's wear as opposed to simply needing to get pumped up...? I may be way off track... But it doesn't do it after it's warmed up.

 

[bhuff30]

I can probably take a video tomorrow morning to see what everyone things.

Yeah, I guess I'm not overly concerned about it because it goes away when warm. If possible, I'll wait until thanksgiving break to do the work. I've got some PI cams to go in at the same time. Just not sure how many parts I need to order... the whole kit with chains, guides and tensioners is something like 270$.