98 Ford Explorer engine/exhaust noise

probably the heat shield around your catalytic converter has a few broken spot welds or an exhaust hanger is broken

Yes it is likely a broken catalytic ceramic brick.

Hard to discern what you mean by dryer noise since you didn't say if it was coming from the engine, exhaust, inside or outside the vehicle. But I'm going to put my experience on a clogged catalytic converter. The pressure in the exhaust will back up into the engine and cause a very annoying wind noise. Like the sound of air from a high pressure tank being released. You local muffler shop will usually do a temperature check on the cats for a low fee or even free.

SOUND LIKE LOW COMPRESSION.EXCESSIVE CARBON INSIDE ENGINE CAUSE ENGINE TO DIESELING KEEP RUNNING MAKE A RATTLING NOISE WHEN YOU TURN OFF IGNITION.

It is most likely an exhaust heat shield or a catalytic converter that is breaing apart inside. Get underthe van when it has cooled off and "thump" the exhaust with your fist to see if you can locate the rattle. Often, the heat shield welds break where they are attached to the catalytic converter. I have fixed many of them by taking 2 or 3 large screw-type hose clamps and screwing them together to make them long enough to reach all the way around the catalytic converter and tighten them down to stop the rattle. If the noise sounds like it is coming from INSIDE the converter, you will have to replace the catalyst. (or ignore the noise)

I'm sorry for your dilemma, I would hate to give an answer, without a few questions. Is it the engine itself that actually gets louder, or the exhaust is where it's sounding louder? what kind of shape does the exhaust appear to be in? Being an older car, assuming with a lot of miles, there are certain things that could pertain to this...What kind of noise? Is it a rattling? An old heat plate could be the culprit, My first thought was if it reverberates back to the engine, it could be the catalytic comb has failed and broken apart to sift into the exhaust to cause blockage and emit noise from both ends, obviously from vibration noises and restrictive back exhaust. Is there a lack - feeling of power?

there are two things that cause this, one is the front engine pulley comes apart, this is very loud and comes from passenger side of engine, the next is the catalytic converter heat shield is broken.

Only thing that comes to mind with description is maybe heat shield on exhaust, getting loose. Wait until vehicle is cooled off and get under there & check any heat shields you see wrapped around or near exhaust, above it attached to floor of vehicle etc, and give them all a little shake or rap with rubber hammer or similar to see if any rattles are present.

Most likely your honeycomb is broken loose inside your catalytic converter.If it breaks into smaller pieces it can start to restrict the exhaust outout & make starnge sounds like a turbo winding up.I would replace the convereter & go from there.Hope this helps

I had the same problem! I crawled underneath the car and discovered that a heat shield on the exhaust header pipe was corroded and rattling against the exhaust pipe. (Before the muffler)
I removed the portion and clamps and solved the problem. Give it a try.