Oh the dreaded steam clean eh. God they should outlaw that these days. There are so many electronic devices, relays ,switches in the engine bay that steam cleaning can cause insurmountable problems. I remember leaving the oil cap off my old citroen picasso, engine oil was everywhere. The mechanic told me to leave it well alone and let the engine heat burn most of it away. Another mechanic said it would keep the engine rust free for years and he was bang right. A dirty engine is an honest engine in my book.