|Originally posted by Patrick:|
And don't trust your aftermarket cats either...
Pulled that off my '86 GT a few years ago.
In many cases, that damage cause by replacing the cat but not fixing other problems.
Burning oil, rich engine, leaking coolant from bad head, etc can overheat "plug" or poison the cat.
|The average light off temperature at which the catalytic converter begins to function ranges from 400 to 600 degrees F. The normal operating temperature can range up to 1,200 to 1,600 degrees F. But as the amount of pollutants in the exhaust go up, so does the converter's operating temperature. If the temperature gets up around 2,000 degrees F or higher, several things happen. The aluminum oxide honeycomb begins to degrade and weaken. The platinum and palladium coating on the honeycomb also starts to melt and sink into the ceramic substrate reducing its effect on the exhaust. This accelerates the aging process and causes the converter to lose efficiency.|
If the overheating condition persists for more than a few minutes, or if the temperature soars high enough, the honeycomb itself may melt forming a partial or complete obstruction, causing a sharp rise in backpressure. A complete blockage will cause the engine to stall shortly after starting, and will not allow exhaust to exit the engine.
Overheat is a big fire hazard. Can easily ignite grass/leaves you park over or burn down the car.
blainelocklair is not OE either.
GM OE Fiero and many others are big flat "pellet" type and have a plug in bottom. Plug is how the pellets/beads are loaded. Used to be you could reload the beads when cat got poison. Bead types can die when the "cage" is rusted out.
Edit to add> My Fiero OE cat is 25+ years old and still passes DE emissions with very low numbers. (sniffer at idle and 2200rpm, no rollers.) I had old Fords 10-15 year old cat and passed w/ low numbers too. Only fail test on one Ford was perform when cat cold. Drive a bit and it passed 2nd test same day.
------------------Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)The Ogre's Fiero Cave
(It's also at the top and bottom of every forum page...)
[This message has been edited by theogre (edited 04-20-2014).]