I have my 4.8 on a stand and it's really dirty. I removed the rockers so that the valves are all shut. Should it be safe to power wash it this way? I'm going to pull the heads and oil pan later but for now I just want to get it clean. I'm thinking with the valves shut and valley cover in place and water pump still on it water can't get into anyplace too dangerous and I'm not going to go crazy with it, I just want to get the messiest stuff off and then I know I'll have to scrub the grimiest of it off by hand.

 

If all you want is to clean the exterior, put the valve covers back on, and duct tape over the exh ports. (and the int ones as well if the manifold is off)

 

The valve covers are on it, I think I'm just being lazy and hoping with all the valves closed I can get away without taping over the ports because it has no manifolds on either side. I just feel like the washer will blow duct tape off but maybe I'm underestimating duct tape.

 

Just pop the drain plug out of the oil pan and let it wash all that old carbon and dirty oil right out of the entire engine.

 

I'm afraid that if you wait too long after washing, you might find things rusted internally that you did not expect.

 

I pressure washed mine when it was still all together to knock most of it off. After I pulled the intake I duct taped everything closed then used a spray bottle, wire brush, and some rags.