Well, this morning I rented a pressure washer and cleaned the 1986 Pontiac Bonneville engine which I plan on using in my roadster pickup. First off, I rented the 1000 PSI unit, lugged it home, hooked it all up, and---wouldn't you know it---darn thing wouldn't run. It just kept tripping breakers in my garage. Then it started to rain like crazy, and of course I am trying to do this in my driveway. Not in a happy mood, I drive back into town (about 5 miles), and all they have left is the gas powered 2500PSI unit . Since I am now pretty ugly about the entire situation, they let me have it for the same price as the smaller unit. ---Back home, hook up the big unit, fire it up, and Yahoo---we got power. Now picture this---its raining like crazy, I'm out there pressure washing like crazy, water out of the sky is trying to drown me, dirty, scummy, water is bouncing back all over me off the engine, my glasses are suddenly covered in crud, but Hey, it's working. I soaked the engine in Gunk degreaser last week, and wrapped the whole thing in saran wrap to keep the Gunk from evaporating during the week, so the pressure washer is being fairly effective. The engine is now in the garage drying, I pulled the plugs and turned it over by hand a few times to purge the cylinders. It still is not good enough for painting. I will have to go over all of the block, heads, and intake with a rotary wire brush, before its good enough to apply paint to. The grease really is gone, but there is a lot of scale and the surface feels all "pebbly", which is probably just the effect of 17 years of heating/cooling cycles on the cast metal surfaces. Now, advise to anyone considering using a pressure washer to clean an engine----#1--get the 2500 PSI unit, I think the 1000 PSI unit would not have been powerfull enough, even if it had worked right, #2--if you are going to rent a unit, pay a bit more and get the unit that heats the water, the one I rented just used cold water from my outside tap, and as we all know, hot water really cuts grease, cold water don't. #3--you can buy a gallon of degreaser from the rentall place which will siphon into the hi pressure stream of water as it is sprayed, however, I don't think that is nearly as effective as applying degreaser 3 or 4 days before hand, and letting it soak #4--try and have a disposable rain suit, or at least some big plastic garbage bags with arm and head holes poked into them to wear, because 80 percent of the water you spray is going to bounce back all over you. #5 have the engine on an engine stand or some type of rotisserie so you can keep turning it periodically to expose all the sides and bottom of the engine. #6--try for a day when it don't rain.