I just finished oil cooler egr cooler welded, and i tried cleaning mine. I have parts cleaning tank with the flamble stuff in it, crap cleans anything i have put in there. And manifold fit, so i let sit for three days , pulled it out little bit gone but not much. I also use purple power from wally world, repeated spraying and hose downs did a better job. If you could let it sit in purple power i think it would clean it , say a few days