Blown head gasket/ black oil in over flow

I don't like head gasket repair in the bottle, but some people swear by the stuff. You could try the Blue Devil product as a last ditch effort, but if it fails the only other option is replacing the head gasket. I would rather fix it correctly.

It may or may not but it is worth a try I had a bad head gasket and add some Bars Leak Head Gasket Sealer worked great never used that brand before but it may work the only thing is if it does not work do not try no more then two times anything after that you could clogg up the cooling system.

Ok thank you sooo much

So how can i flush my overflow its full of black oil

Should just be a couple of bolts holding the over flow tank to frame just remove bolts and remove rubber hose going to it.