Detroit 60 12.7 - Turbo high boost

Guys, I am need of some help!

I have a 2005 Classic with a Detroit 60 12.7 with EGR. This motor has 300192 (miles) on the ECM with 12858 hours.

The truck has literally been my savior compared to the other two I have up until now.


Here’s the breakdown:

Driving down the VA turnpike climbing hills I noticed this squeal only when in the throttle and sounded as if it was from the turbo. Almost sounded like a dry bearing. Then it would go away. Further, I then notice the turbo building boost to 40-45, normally around 30-35 and no higher. The turbo was working harder but the truck seemed to be doing the opposite almost as if the back pressure was choking it out. I feel performance is much better at the normal 30-35 range.

The truck would throw a code (but quickly go out) and it would make a loud pop. About the same time the truck would kind of buck in a sense and PSI would drop to normal. And then it may do it again or may not for days or a week.

Shortly after noticing this happening, it did it while en route to a shipper. Empty trailer and on no grade, just flat road running about 65, it was boosting high, then pop, then normal. When I stopped at the shipper I did a walk around and had antifreeze all over the right side of the bumper, fender, wheel and front mud-flap to the point it was just dripping from every where, it came from the overflow tube. I now have pressure building in the coolant system. No pressure prior to the turbo issue.

I have not ruled out the compressor nor the EGR due to thinking this may be tied to the issue with boost. As far as the head and head gasket goes, I have no mixing of anything, and no smoke.

Really just need a starting point. I feel like this boost issue has created the other problems and I’d like to get it resolved asap. Thank you in advance


* pulled codes from truck (not thru computer, just thru diag button on dash) and are as follows, zero active:

25, 43, 63, 31, 16, 38, 46, 39, 68, 22, 23, all inactive at the moment


Did replace radiator cap, also to note I believe the CAC has a hairline crack as I can feel air when I walk in front of the truck. All CAC boots, hoses, and clamps have been checked and are in good condition.

As I think of other things I’ll update. Anything needed, pictures or information, I’ll be glad to provide.