Hello,
I recently installed a remanufactured 6.4L in my 2008 Super Duty F-350. My mechanic mentioned there are not any specific break-in instructions for the engine. In the past, with rebuilt motors (though never a diesel), I have always been told to change the oil after a certain number of miles or keep the RPMs under a specific limit for the first 2,000 miles. Does anyone have any insight or recommendations on this for a diesel engine?
Drive it like you stole it.
Especially while it’s still under warranty.
The sneaky 6.4 Never in my life have I been more terrified of a vehicle. It’s similar to the 350dx, but this is where I change my mind. If correctly reconstructed and carried out as described below Hammer down and load her up.
It was rebuilt by Ford, but it’s been a nightmare since I bought it. The oil cooler was faulty from the factory, so they had to pull the cab again to replace it. Then, both turbos started making noise, which meant pulling the cab yet again. I’ve always been a Ford guy, but this experience has really changed my perspective on them.
A Ford reman should come with a 3-year/unlimited mileage warranty, so go for it. Unfortunately, 6.4s can be a hassle to work on, with cab-off jobs for minor issues. Using full synthetic oil is always a smart move—I’m running Schaefer’s 5w40 in my 6.0. I still change it every 5,000 miles because I push it hard.
Wait until the engine is broken in before using synthetic oil. Typically, I would connect a trailer for the first 100 miles, replace the oil, do it again at 2000 miles, then switch to synthetic at 5000.
If it’s an OEM engine, I’d recommend taking it easy for the first 1,000-2,000 miles. But if the engine came from a reputable independent shop, then go ahead and drive it hard. I’ve never heard anyone complain about their vehicle if they take good care of it.
My dad always taught me to gradually extend oil changes to 3,000-5,000 miles. Start by changing the oil after the first 500 miles, then at 1,000, and again at 3,000. If you want to go for 5,000-mile intervals, change it at 5,000 miles and then every 5,000 after that. Personally, I aim for oil changes between 3,000 and 5,000 miles. I wouldn’t recommend going more than 5,000 miles between changes, especially with the 6.4, which is what I have in my truck.
Don’t worry it will break
Making diesels run is the best way to break in. Load it up and drive.
Put it to work right here if it isn’t leaking or producing strange noises when it first starts up.