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Q: Check Engine light; catalytic converters failing

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The Check Engine Light came on. Two codes came up saying two of the four catalytic converters are failing. This caused my truck to fail a smog test. I noticed my coolant overflow kept draining down to nothing after I filled it, but I don't see a leak.

Hi there. It sounds like you have a few issues going on here. If the catalytic converters are failing, then the converters will need to be replaced. They tend to either fail and become clogged causing a loss of engine power, or they simply fail and no longer react as they should. As for the loss of coolant, this engine has a history of head gasket failures even if the engine has never gotten hot. Most of the time this occurs on the driver side of the engine. A block test will reveal the problem area, but many times I’ve had to use a bore scope to look inside of the cylinders to find where the coolant is going. It is typically the rear cylinder on the driver side. If you need further assistance, a certified mechanic, like one from YourMechanic, will be able to diagnose the coolant issue.

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