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Discussion Starter · #1 ·
Hey Guys:

Could use your thoughts on what my truck is doing.

Backstory: Truck has 160k. Ran great. Only mod is Bully Dog programmer. Run on "Performance" tune (est. 75+ hp). Would get black smoke whenever you romped on it, but no other smoking. (In hindsight, I think it had low boost since I got it a couple years ago. Boost around town >10 psi. At WOT maybe 15-17 psi?) If I romped on it, my EGTs would see 1200 <--unloaded.

Labor Day weekend I pulled heavy (20k lb GCVW) for 600 miles. Couple good hills. Saw 1200+ EGT a couple times before defueling. Heard a good "pop" at some point when under throttle (sound from under hood) but didn't notice any performance change. Ran out of fuel once (missed out exit.) Shut off engine before it died. Was stuttering but didn't die. At one of the fuel ups, noticed that the thermostat housing had slight weep. Pic below. Looks like it has been weeping for a while.

Now back home and usual daily driving, I'm getting white smoke when accelerating in certain instances. No smoke at idle. Feels like less power but may be in my head. Per the Bully Dog, my fuel mileage has dropped (Uses a school grade instant monitoring system. Showing an "F" now. Usually says "B" or "C".)

Did the oil cap test and no noticeable puffing. Cap will sit on spout (vibrate off eventually). Oily valley but been that was since I got it. Had two prior fuel bowl leaks fixed a while back, but definitely freshly damp. Good bit of oil in air intake tube. Pulled DS intercooler tube to measure inlet/outlet and lots of oil there too.

My first thought was boost leak, so I'm headed down that road? Going to pull both tubes and intercooler, drain, clean, and reinstall. Have all 6 boots, new clamps, and plenum inserts on the way from RiffRaff.

Also on the way is new billet tstat housing and tstat, new degas bottle cap, upper hose, CCV delete kit, and overboost code regulator.

Anything you'd suggest checking while waiting on these parts? Reading around about this symptoms, and if not a boost leak, then maybe turbo seal leak or EBPV stuck?

Thanks all!
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