Intermittent Turbo Boost HEADACHE!!!

Hey what’s up guys!

Wanted to get some advice or knowledge regarding a problem I am having with my 06 Freightliner Columbia. I have a 60 series Detroit Engine 14L. I am loosing turbo boost intermittently at times, sometimes for a few hours or a few mins. As soon as I turn off the truck for 5 Mins and re start it. Turbo boost on. As of now I have changed VPOD, VPOD Air Line, VPOD Harness, Turbo Boost Sensor, Turbo with Actuator, CAC & Hoses & Boots. They did an EGR delete on truck before I bought it. Truck was running fine till a few weeks ago, it started derating. This is my second Columbia and always have had similar problems with them I get code SID 147 FMI 2 . Any advise will gladly be appreciated!!!

 

To be honest, I haven't checked with gauge. Seems significantly less boost than I had a few months before. I would say 1/4 less than when it was running good. And then it just all of a sudden completely stops boosting. I am changing Delta Pressure Sensor now. See what it does. My gut feeling is telling me the EGR valve is to blame.

 

I have that thought as well, I took off the compression side hose/pipe coming out of turbo. I found small oil leak, would that be a definitive sign of bad Turbo? Not a lot of oil just a bit. Turbo shaft turns smooth and is firm in place. Would excessive crankshaft pressure cause any turbo problems? Also my coolant temp stays around 150ish and 170 with loads. Is this normal for temp to be running this low?