30.12.2009 Chinese Navy has 16 modern Russian-made warships [12 Kilo-class diesel subs and four destroyers] which need to be repaired and upgraded in the middle of their lifecycle.
Most of those ships were delivered in 90-ies. Russia offers to carry out capital repairs at own shipyards, although the Chinese wish those works to be performed in China involving Russian staff and equipment. In its turn, Russia is not satisfied with such turn-up and considers China intends to cheapen cost of repair works and even to steal Russian maintenance equipment.
The Chinese wish the high quality repair and say Russian shipyards have no capabilities for that. Indians recently faced that fact when they sent Kilo-class subs for overhaul and are still waiting for delivery of an aircraft carrier. China tried to make their shipyards capable to repair Kilo-class subs and turned to Ukraine for assistance. However, Ukrainians have no information about Kilo's latest improvements; so, the Chinese want to get this information from Russia.
Presently, both sides have to come to an understanding in this area, although the Chinese seem to manage the repair by themselves using domestic equipment and native staff.
Source: Military Parity, photo: Chinese diesel subs of Project 636 Varshavyanka (china-defense-mashup.com)