Oil capacity: Let me check. The DF037 engine has an oil capacity around 6.5 to 7 liters. Oil filter needs to be considered for maintenance.

Also, the compression ratio is relatively high for diesels, maybe around 22:1 to 23:1? Yes, common for that era.

Environmental impact and emissions: As a pre-Euro standard engine, it does not meet modern emissions standards. The DF037 would produce high particulate matter and NOx emissions, contributing to urban pollution if run on the road today.