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c/diesel-mechanicshugo50hugo5018d agoProlific Poster

A 2008 Duramax with a ghost code that took three days to pin down

Got a truck in the shop that would lose power but only after a full hour of running. No stored codes, nothing. We swapped sensors, checked the fuel pressure (it was fine), and even looked at the wiring harness. The fix? A tiny crack in the plastic intake elbow after the intercooler that only opened up when the engine got really hot and the plastic flexed. It took us three full days of on-and-off testing to finally see it with a smoke machine. Anyone else run into an intake leak that only showed up under specific heat conditions?
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2 Comments
betty_scott18
My buddy's shop had a similar thing on a 6.7 Powerstroke. The plastic charge air cooler pipe had a hairline split that only leaked under full boost and high temp. They finally found it by spraying soapy water while the truck was on the dyno.
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loganhart
loganhart18d ago
That soapy water trick from @betty_scott18 is a classic for a reason.
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