In April of 2002, Jereh Engineers overhauled one CAT D348 engine for Tianjin Dagang Oilfield. There are several such engines in this field. These engines were manufactured in the 1970's and served this oilfield for over 20 years. And Caterpillar Inc has already stopped manufacturing such engines years ago. People of Dagang Oilfield had planned to discard all the D348 engines useless, but in order to meet the requirement of production, oilfield leaders and engineers raised one overhaul plan for one of these engines, and invited several companies to take part in such overhaul. After learning the difficulties of overhauling this engine, some companies withdrew. Jereh engineers who completely know their maintenance capability brought up their overhaul proposal after having checked this engine.

After the spare parts and tools ready, Jereh engineers went on working for more than 10 days and completed this task. Having carefully checked the test result, the leaders and engineers of Dagang Oilfield satisfactorily signed on the certificate of maintenance qualification. During several months of running, this CAT D348 engine triumphantly accomplished the production tasks.