What could this be. Pictures inside

[gonzo1949]

I took the venturi pipe off and it's got this brownish color instead of the normal black soot.

[gonzo1949]

[gonzo1949]

I'm assuming coolant.

[hhow55]

Is it also showing up behind the erg cooler?

[gonzo1949]

Not that I can see

[Erics diesel]

It's the combination of anti freeze and nox gasses it's caused by a leaking egr cooler I would replace it immediately and clean the egr valve

[gonzo1949]

Yea I figured. Can that also pressurize my coolant overflow bottle.it's been doing that on hard pulls . That's y I checked the venturi pipe.

[gonzo1949]

I wish there was an easy way to eliminate the cooler,egr valve and piping

[Erics diesel]

Yes if coolant can come out then exhaust preasure can get back into cooling system.