Is this much blow by normal for a 16 F-350 with 80k miles?

I’m thinking about buying a 2016 F-350 with 80k miles. The truck looks pretty clean, but I’m new to diesels and don’t want to get ripped off. Is this level of blow by normal for the truck’s age and mileage?

That seems fine. But I would recommend changing the crankcase ventilator filter if you’re worried about it. It can get clogged and cause too much blow by, which might end up blowing out gaskets and leaking oil. My dad’s 2017 had this issue, and it ended up blowing out the upper oil pan seal, leading to an $8k repair for a $30 filter.

@Landry
Totally agree with this. Changing (or deleting) the crankcase filter is one of the most overlooked things with these trucks.

Yep, give this guy the credit he’s due.

Yes. What was the pressure like when you took the cap off?

Val said:
Yes. What was the pressure like when you took the cap off?

I did the upside-down cap test, and it just stayed in place. Since I’ve never owned a diesel, I’m looking for feedback from those with more experience.

@Kerr
Looks like you’re good to go. It seems normal.

That’s perfectly fine.

Steam from moisture on a cold start and crankcase gases escaping from the filler neck on a warm engine is normal. This happens with both diesel and gas engines. What matters is how hard the air is pushing out.

A general rule of thumb: flip the cap upside down, and if it stays over the hole, you’re good to go.

I can definitely confirm that the crankcase filter clogging is a real issue. I didn’t know about it until mine clogged up, ruined a couple of injectors, and blew almost every seal in my engine. It cost me around $12k. I ended up replacing all the injectors and even got a steel oil pan, but it wasn’t a cheap fix!

@Jesse
From what I’ve read, a lot of people remove and reroute the crankcase filter to vent it to the atmosphere via a hose. Seems to be a popular modification.