2000 3.0 Flex with p0420 code after blowing head gasket

[Cleanster]

First thanks for the look. I have a 2000 3.0 flex XLT 4x4 and I just blew the second head gasket on a 2nd motor at about the same mileage as the 1st, about 110 k for both. Did not cook the motor this time and was able to get away with replacing the heads. As with the first time most of the coolant went out the exhaust system. I now have a P0420 code and am getting bad mileage. My question is will the system eventually burn off the contaminate or should I look to replace the cat and both O2 sensors? Thanks again.

 

[adsm08]

Drive it for a few weeks, until all the coolant is burnt out of the cats, then clear the codes. If they come back replace the sensors, clear codes, try again. If the code comes back again, then get cats.

Coolant isn't good for cats, but it can be boiled out. On the other hand it is really bad for oxygen sensors, and they won't recover from contamination.

 

[Cleanster]

It has been several weeks now and my truck sounds like a baseboard heater when the fins begin to warm when I turn it off. The trucks runs fine and the fuel mileage is back to per blown head gasket levels of about 20 mpg mainly around town driving. Any thoughts?

 

[Cleanster]

Ran a bottle of Cataclean through today. Quieted down the noise coming from the cat will clear the code and see what happens.

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