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Just a slideshow and video of a 2.8l GM engine I rebuilt for engine repair class, from blown headgasket and milkshake coolant/oil to successfully running and holding oil pressure.

Hey guys, I have a 1990 Jeep Cherokee Sport, 4x4, 4.0, 5spd that has a light knock. Its crankcase breather thingie was rotten so I got a new one and installed it, and when I did I noticed that inside at that point, there was a serious buildup of sludge. Looked like someone took some rubber and oil and blended them together and poured it in. How might I get rid of this? Pour seafoam in that hole? In the oil? Will it actually get high enough to clean that out? And last, even if it does get up in there and cleans it out, I'm seriously worried about it doing more damage to the engine than it's worth. And last last, after all this should I switch to 15w40 diesel oil to help that knock?

Thanks for answering the questions I've been posting the past few days, now here is why I was asking. I was trying to address oil leaks and removed my valve cover to replace the gasket and found some rather bothersome Oil sludge. I plugged the push rod holes and scraped off what I could access. My plan now is to pull the oil pan and clean that out and install a new rear main seal and pan gasket. while I'm in there I've been advised to check the timing chain slack and rectify if needed. I'll also replace the crank case ventilation components since the were sludged solid. My question to those who know more about this engine, is should I also remove the timing chain cover to remove sludge in that area. It seems the valve train sludge is sort of common but I haven't heard anyone mention sludge under the timing chain cover. After it's all back together I'll probably add some Marvel Mistery Oil or Auto-RX and do repetitive oil changes for the next several thousand miles hoping that the additives will clean out any oil passage sludge. Appreciate any input.