help again

[2000_EXPO]

hey guys I was under my 4.6 expy today and I have been hearing a strange rattle. I was worried so I was looking everything over a discovered that it was my cats. does this mean that there plugged or what? because I didn't think there supposed to do that.

 

[KWT2000]

they are due to be replaced well which ever one is rattleing most likely the driver side front cat

 

[Copper93]

If they are only rattling, it probably is the heat shield. The only time they need replacing is when they are clogged. Are you having any reduction in power or "egg" smell? Cats should last the life of the truck.

 

[KWT2000]

If they are only rattling, it probably is the heat shield. The only time they need replacing is when they are clogged. Are you having any reduction in power or "egg" smell? Cats should last the life of the truck.

the early modular engines had a thing for burning up the front cats and the catalyst will come loose and rattle and can go down stream and cause more problems

 

[FordandPolaris]

the early modular engines had a thing for burning up the front cats and the catalyst will come loose and rattle and can go down stream and cause more problems

Hmm that could explain some things for me... If I remember right you deleted the rear cats on the last expy right? Any difference in torque?

 

[KWT2000]

Hmm that could explain some things for me... If I remember right you deleted the rear cats on the last expy right? Any difference in torque?

low end was much more noticeable and nice to have when wheeling around gained a small amount of mileage also and the sound was unlike any other 5.4 around locally

 

[jbanks]

I thought the same thing about the rattling heat shields. There is even a Ford TSB covering 97-99 Expeditions(and a ton of other Fords) about putting "Worm Clamps to secure the rattling heat shield" - Here's the TSB : http://www.drive9.com/wp-content/uploads/2006/11/98-20-10.pdf

I went to two different Ford dealers to see if I could find the clamps "FOTZ-5A231-A" so I could try them to see if they made a difference. It's hard to grab the heat shields while they were hot to see if I could stop the rattle. I was using a hammer to hit them while grabbing the heat shields while cold to see if it was making a difference. It seemed to, so I spend my $16 on the clamps.

The clamps didn't work so I bit the bullet and ordered a new replacement converter assembly for the drivers side. It should be here today. I have been PB blastering all the bolts everyday hoping for an easier removal.

Here's the thread I started about the problem: http://www.expeditionforum.com/f42/98-navigator-5-4l-4x4-rattling-noise-20993/

Does yours sound like my video?

 

[jbanks]

By the way. I'm pretty sure the one that is rattling in mine is the drivers side rear.

 

[KWT2000]

if the catalyst is broken up when you replace be sure to check the Y pipe and muffler for blockage

 

[Mediamonkey11]

How many cats are there on a 4.6 or a 5.4?

 

[BIGRED03]

How many cats are there on a 4.6 or a 5.4?

On a 5.4 I have seen two located just down from the headers, 1 on each side of block. I thought the cans further down were resonators and mufflers. IMHO that is.

 

[FordandPolaris]

How many cats are there on a 4.6 or a 5.4?

1st gen trucks such as yours and mine have 4 cats on the 5.4L. There are the two normal looking ones, and then there are two smaller ones upstream from those. Not sure on the 4.6L

 

[Lightnig]

if the catalyst is broken up when you replace be sure to check the Y pipe and muffler for blockage

^^^ THIS!!!!


I had a set where the internal 'honeycomb' of the catalyst itself broke up, leading to a rattle type sound.

I didn't worry about it at the time because performance and power were quite good, actually better than it had been prior to the rattle first appearing. The problem was that the cat 'guts' broke apart in various sized pieces, several of which were small enough to be sucked back into the cylinders during very high vacuum conditions (fully closed throttle immediately following full throttle).

The very high hardness of the exhaust deposits on the catalyst agent scored the heck out to the cylider bores and wrecked an otherwise perfectly good Subaru engine...




Never mind the economy or emissions aspect of a bad cat, from direct experience I know that full inspection and immediate repair of a (even simply suspected) bad cat is required ...