cat conv fouled?

[joeb]

my car had a headgasket leak for over 1 year. finally got bad toward the end and used a lot of coolant till i parked it. fixed motor and have been getting 02 codes for awhile. lately it is 1139. i used to get 0140, 0141, but that seems to have stopped. does dumping a lot of coolant into exhaust shorten the sensor life and perhaps foul the cat? or do the parts seem to recover after awhile? car does not run perfect. i wonder if a fouled cat is a possibility?

[Cadillac Jim]

I ran my car too long with a bad head gasket and partially clogged a cat. It wasn't bad, but the car didn't perform to its full potential. And, no, they don't recover from fouling from lots of coolant over a long period of time. Cats may recover from things that can be burnt off or vaporized. If the coolant contains silicates (green), forget it. Apparently red can do some damage too. You can have a 49-state OBD II certified low-restriction cat on your car for a little over $100 if you want to go that route. If you are in CA you need to call a knowledgeable source like Summitt Racing or a manufacturer like Magnaflow, etc. Here is mine:

http://www.summitracing.com/parts/MPE-94109/

Here is one that is found under the "50-state" search term:

http://www.summitracing.com/parts/MPE-43009/

Note that the 49-state converter is about $80 but the 50-state is about $230. I think that the extra $150 goes to the certification costs and any configuration and manufacturing requirements that CA deemed necessary whenever those lawyers in Sacramento pondered the air in Las Angeles and San Diego.

You will need to weld the flanges with HO2 bungs from your existing cat onto either of these to complete the installable cat, which is then installed by a simple undercar bolt-on operation. This cost me about $125, installed. Figure $300 for a 50-state low-restriction cat.

[caddypete]

Coolant destroyes O2 sensors. And a bad O2 ensor is going to effect how the engine runs, would look there before thinking bad converter.