I have a 2001 7.3L Ford diesel truck running 15W40 Delo. The temperatures have been dropping at night down to the 20’s. In the morning, I notice for the first few seconds after starting that the engine runs a little rough, below 40F. I have a high pressure oil (ICP) gauge and can see that the pressure at start is much higher (1800psi versus 1000psi normal) at these temps and would guess this is from the oil being thicker at colder temperatures. The pump is likely working a lot harder to push the oil through the injectors. Based on this I am considering running a 5W40 oil. I know that Rotella, Delo, and Amsoil have this weight of oil. Any recommendations based on these different brands? From what I have read, the 5W40 is fairly popular for these diesels during winter months. A while back, I did run the Amsoil series 3000 which worked pretty well cold starting, but was not sure the 5W30 was the right oil for these diesels or not.
I have been running Amsoil filters. Are the Amsoil oil filters pretty decent or are there better options out there? Thanks.
I have been running Amsoil filters. Are the Amsoil oil filters pretty decent or are there better options out there? Thanks.