1998 Dodge Dakota Catalytic converter noise?

MJWILLERT2

MEMBER
1998 DODGE DAKOTA
3.9L
V6
2WD
AUTOMATIC
106,000 MILES

I have a rattling noise coming from underneath my truck that is mostly noticeable when it is idling. At first I thought maybe a baffle had came loose in the muffler. I took the truck to a muffler shop and was told it was my catalytic converter. The muffler will also need to be replaced since it has holes in it. I just wanted to know if I would be getting a rattling noise if my catalytic converter was bad. The truck seems to run fine and I haven't noticed that my gas mileage has gone down. This rattling noise on my truck has been there since last summer but I haven't put many miles on the truck since then.

3 Replies

CARADIODOC

MECHANIC
33,749 POSTS

The catalyst is a very porous, soft rock and they do break loose and can rattle. Bang on it with a rubber hammer and you'll hear it rattle if it's loose. The proper repair is to replace the converter, but before you do that you can try a temporary fix. Drill a small hole in the bottom of the housing, start a self-tapping bolt to make threads, then take the bolt out and grind the point flat and smooth. Run that in just until it won't rattle any more.

The catalyst is breaking apart and chunks are going out the exhaust, and eventually the Engine Computer is going to detect that no change is taking place in the converter, and it will set a diagnostic fault code and turn on the Check Engine light. Pressing on that bolt might make it break up faster, and holding it from rattling might make it break up slower.