cleaning aluminum engine block

A question came up by a friend recommending a hot cleaning for the engine.
I said NO and here is why.


HOT TANK

Hot tanking is the traditional way to clean dirty cast iron engine blocks, heads etc. The hot tank is just a big metal tank with a very nasty, caustic hot water solution in it. The parts are submerged in the solution and allowed to soak for many hours with the solution slowly circulating around them. This is sometimes referred to “vatting” or "boiling" the block, because it is being soaked in a large “vat” of almost boiling liquid. A hot tank does a good job of cleaning engine parts but does not always remove all of the rust and old paint. Because of environmental rules and regulations, a lot of shops are doing away with this method of cleaning.

Aluminum parts cannot be cleaned in a hot tank as they will dissolve. 

Also on the question of magnaflux on the block, It wont work because its aluminum



Before we go into the “how” of magnetic particle inspection, let’s look at where it will work and where it will not. First of all, being magnetic, it requires a ferrous metal base. For the most part, with our oldercars and trucks, that’s not a problem. Most engines and engine parts are iron or iron-alloy based. It won’t work on aluminum engine blocks, pistons or other aluminum parts; pot metal (not used for an engine block, but frequently for components), copper or brass, and most stainless steel. The MPI has to set up a magnetic field within the metal so that the identification powder – usually an iron oxide – will react to the magnetic waves.