Year of publication: 1999
In our construction company, we operate a wide variety of construction equipment. We also have our own fleet of trucks. All engines are regularly monitored with OELCHECK lubricant analyses. Based on the analyses, we usually change the engine oil at longer intervals than specified by the manufacturer. Now, following a recommendation from our lubricant supplier, we switched to a supposedly higher quality, semi-synthetic diesel engine oil SAE 10W-40, type SHPD. However, after the change, the oil already turned noticeably black in a short time. What could be the cause?