An old diesel mechanic told me to stop using synthetic oil in my 7.3 Powerstroke
Honestly, this guy named Mike at a shop in Phoenix told me that synthetics are too thin for high mileage IDI engines. I figured he was just stuck in his ways, but after 8 months, I started losing oil pressure on hot days. Swapped back to 15w-40 conventional like he said, and the pressure gauge stopped bouncing around. Has anyone else had a shift in oil type fix a weird problem like that?