Smoking 767 engine on landing
 

I am researching a recent incident involving a Boeing 767 jet. According to ground fire crew, there were small flames and smoke coming from one engine on landing.

An airline spokesman said this was a problem with the water system, that it had been fixed without replacing parts, and that there were no flames- just smoke.
The on board fire fighting mechanism was not sufficient to stop the smoking - firefighters succeeded with foam.

1) Can anyone suggest possible causes for this reported phenomenon?
2) can foam damage engines?

Many thanks
PD