So at work we have a 2011 ford with 125,000 miles bone stock, lots of highway miles. Just had the turbo replaced by Ford, it was smoking white and eating oil.. Here is where the fun starts. Got the truck back and after one day another check engine light, they said knock sensor, I said change it, they called back and now they say I need a whole new exhaust system tot the tune of 3400$ can I just try to run it to "clean" it out, and knowledge will be appreciated.. They say it is because it is coated with oil, has anyone ever hot tanked or cleaned these things?.