Join Date: Mar 2017
Location: Calgary Alberta
I would stay away from a full syn for the first oil change or two. Reason being is that during break-in a synthetic oil is too 'slippery' and will not allow for proper seating of rings etc. GM diesel mechanic suggested to run 15-40 for the first 10,000 km (6,000 miles) to break in the engine. This made send to me because when I rebuilt a motor for my T/A, I started it and ran it for the first year or two on Mobil 1 5-30. I have Chrome Moly rings and they would NOT seat and I was burning oil at the rate of ~1 quart/ 250 miles - yikes, not good with a new motor...I ran it one season (about 1000 miles) with 10-30 conventional and problem has gone away. I am now back to a 5-30 in the bird with no oil consumption issues. Currently I have ~15000 km (9000miles) on the 2017 L5P and it is on oil change #3 (#1 at 1600km, #2 at 5500km, #3 at 11,000km) and has been running a conventional 15-40. I will be switching over to a 5-40 prior to this winter (last winter was a chilly one here so with 15-40 in it, it spend a great deal of time plugged in...). Filter has only been AC Delco...
2017 SRW 3500 SLT Z71 CC
1978 Trans Am, 400, factory 4 spd, 3:42 posi
oh, and I love fossil fuels...