WHY? It dries hard to the touch. Is your engine compartment COMPLETELY dry before application? Never had a problem, the best I have ever used.
I saw this and based on the hype I've seen, I bought a couple of cans when I saw it at a local AZ. I actually tried it. I guess I didn't use it right as I didn't go for a drive after using it. The engine looks OK. However, I'm extremely leary of spraying some chemical on a part and that's it. I'm uber-anal when it comes to engines... Polished each Bosch sensor to a mirror finish with a Dremel. My expectations were low and they were met. I think CD2 is a good engine dressing for a new engine with those big plastic covers but for an engine that's seen some serious use, it's just not going to remove the years.
If the engine is pretty gunky, usually I'll hit it with a diluted APC to break it down then go over it again with CD2. That usually does the trick.
It's only a dressing. Not a cleaner, not a rust remover, not a scrub brush, not a Dremel tool. Methinks you ask too much of a simple spray on engine dressing.
