A quick way to clean up an engine that has been idle for a long time is to use Diesel fuel. Change the oil, using whatever inexpensive "bottom shelf" generic stuff is available at Walmart, and add 3 quarts of Diesel to the crankcase so the crankshaft counterweights and connecting rods can dip down into the oil/Diesel mixture. This will splash the mix around like the agitator in a washing machine, and break loose any sludge or other debris, as well as possibly dissolving carbon deposits under the piston rings, etc. Run the engine at a fast idle for 15-20 minutes after it reaches normal operating termperature. DO NOT DRIVE THE VEHICLE OR PUT ANY LOAD ON THE ENGINE- - - - -1,000-1,500 RPM max. Drain the mixture while it's hot, taking dirt, sludge, and debris with it. Refill with good oil, (I like 15W-40) and change the filter, if the engine is equipped with one.
This will accomplish one of two results- - - -you'll either have a good running engine you can drive, or you'll create an oil burner that needs to be rebuilt because the piston rings are worn out, and all that was holding them tight against the cylinder walls was carbon and sludge packed behind them. In that case, you'll need to pull the engine and rebuild it- - - -but it's going th be much cleaner than it was before, easier to work on. Win- - - -Win!
Jerry
