1994 530i Steam Cleaning Engine & Waxing & whereabouts of BMW Club?

[joshua43214]

I cant imagine why it would be reccomended to have the engine as operating temperature. I think it should be cold, you dont want to hit a hot metal with cold water, this can cause cracks, deformation ect. No matter what type of metal. A cold engine with a good degreaser and mild pressure will do the trick.

-Ben

This is a myth.

Just imagine what happens when you start the car in sub freezing weather, jump on the freeway and the T-stat opens. The engine is suddenly flooded with super frigid water from the radiator. No cracks.

Your engine is designed to handle this stress.

I have seen old cast iron exhaust manifolds on inline 6 cylinder cars crack this way when they don't have good methods of allowing for expansion, but BMW manifolds are well designed.

[BlueM60]

No, it is not a myth. This is simple physics, if you take ice cold water from a hose and completely soak an engine that is at about 200 degrees, your causing that metal to suddenly contract, it may not always crack but its never a good idea. A Cast iron is not the only metal that will deform under such conditions. The engine should hardly ever get wet in the event of a water puddle etc, its basically sealed off. I would never saak an engine at full operating temp, warm is ok, and i agree, dont steam clean because of all the aging connectors under the hood, a quality degreaser with a mild pressure will do wonders.