DD15 oil change/fuel filter interval

Detroit says 50,000 miles I was doing mine at 25,000 miles sampled a few times and it came back clean... my worry was if a injector started leaking I was scared of damaging the engine running it so long..

 

with shell t4 he could probably go that long

 

I have a DD15, 2016 model Freightliner, and what I am starting to do is get oil samples done every 10k miles or so.

Two oil changes back, the shop put 5w30 full synthetic in the truck, instead of 10w30 semi-synthetic. After 15k miles, there was some fuel mixing in the oil. I changed the oil at 20k, and put 10w30 semi-synthetic back in it. After 15k more miles, I got a new oil sample taken, AND changed the oil again with 10w30 semi-syn to be sure I got rid of the majority of the thinner full synthetic oil. From this point forward, I will be getting oil samples taken at 10k or 15k intervals, and change the oil at the first sign of degradation.

 

How would semi synthetic lesson fuel contamination? What am I missing here?

 

Nothing to do with the synthetic or semi-synthetic part of the oil's nature. The semi-synthetic oil is a thicker viscosity oil. Thicker oil tends to protect a little better when the engine has some wear on it. My engine has about 555k on it now.

When I get the current oil test back, there's a good chance that it will indicate fuel buildup in the oil again. If that's the case, I'll need to start thinking about some engine work.

I don't think it will. The truck burns zero oil. Never has. I think the thinner oil simply allowed a bit more fuel penetration past the cylinder rings.

 

I find this fairly simple.

Hook up with an oil analysis lab, and sample every 10k.

Learn about oil.

Change your oil when the analysis indicates it is time to do so.

 

I have the dd13 and I change (bulk oil) every 10-12k miles.

 

Changing your oil on dd13/15 every 10 to 15000 miles is a waste of money. These new technology engines are designed to go 36k to even 45k which some of us don't tk that kind of chance once the warranty goes out. I just sold a isx 870 with 1m 200k and changed the oil every 20k miles and that engine didn't have a blow by or used 1qt of oil. The main thing on these dd engines is to do premaintenance. Def filters and clean the injectors. Change your Dpf filters and change your inlet and outlet nox sensors. Check your plastic interfender on both sides and make sure they are not rubbing against your bunk water lines and especially the drivers side where the Airlines run right up against the fenders. Believe me cut a notch out of the fender bc it will cut that Airline. Don't tk your truck to freightliner if your city horn stop blowing. Tk the big cross section that holds your horn botton up and turn it over. There's a wire that will pop loose from the horn button on the bottom. Push the wire back in and push the horn button and wala your horn blows again. Mailman