Bad Catalytic Converter? or something else? | Ford Explorer Forums - Serious Explorations

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Bad Catalytic Converter? or something else?


April 27, 2017
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Year, Model & Trim Level
1993 Ford Explorer XLT
Hello Everyone,

It's been a while since I've posted on here. I've been stuck at home for the past year because of covid but I'm trying to get my Ex in running shape to be able to drive out west (I'm In Wisconsin). I got my long to-do list and at the top of it; a rattling noise while I'm accelerating. Actually my valve cover or rear main seal or both is leaking so not quite the top but its up there.

The noise only occurs when I'm accelerating at a normal to easy rate and only in 2nd and 3rd gears. It started doing it last December (2020) and has gotten progressively worse. I'm thinking it's the catalytic converter. I had a Ford Escort in high school that had one do the same thing. Just sounds like a bunch of rocks or a metal chunks rattling on metal when I'm going like 15-20mph and 25-30mph and accelerating.

Just wanted to see if anyone had any input to help me confirm my thoughts.


It's probably the heat shield coming loose and rattling. My Navajo does that. I was surprised to see it still installed when I bought it. Almost all my trucks do not have heat Shields on them any more. They have fallen off or have been removed over the years. Most people put large hose clamps around them to quiet them down.

If you remove your shields, be mindful about parking in tall grass. It's small, but there is a chance it could start a fire.

My cat shield hasn't come loose on my '98 yet but a couple of pipe shields just before the muffler did. I just took some 12ga solid core household type bare electrical wire and wrapped it around to secure them. I intended to do a fancier job later with stainless straps but never got around to it... has lasted ~8 years so far.


I checked out the heat shield on the cat last night. I noticed one of the pieces that holds it on (I think its welded to the cat) was gone and the whole shield had been pushed up against the cat. I'll take some photos and post them a little later. So I bent it back and drove a few blocks as a victory lap before it started rattling again. I guess one more detail I didn't think of or remember is that it's only doing it once it warms up a little bit. If I let the truck sit for a day or two and I get in and start driving it won't start rattling for like a couple of minutes.

I just noticed the one thing but I didn't look over the whole cat yet so I'll let you know if I get it solved.