DPF retrofitted, but still use oil with DPF approval (Low SAPS)?
Hello first of all, I drive a Mercedes-Benz W211 E200 CDI (2003) with an OM646 and a retrofitted diesel particulate filter. I've read various posts ranging from "Retrofitted is an open system, so everything's fine" to "DPF will clog up if you don't comply with the approval with additive 1 (e.g., MB approval 229.51). My…