6.7 vs 5.9 cummins oil leaks

[The motor guy]

So I own both of these trucks. The 1999 5.9 leaks just about everywhere with 215k.
Now my 2007 6.7 with 240k doesn't even have a damp spot underneath. What gives? I've owned and maintained the 07 since new. No telling on the older truck, have only owned it a year. Are oil leaks a sign of poor maintenance or not really?

 

[The motor guy]

I do think that's the one good thing about ccv. Creates more of a vacuum instead of positive crankcase pressure like the older truck probably does.

 

[cptbarkey]

My 2003 doesn’t leak because I fixed the leaks.

I think your expectations and comparison are not congruent. Your 6.7 leaking is inevitable. A driveway isn’t an indicator, get under and look. Oil loves to cake up with road garbage and wind blows it back all along the underside.

 

[D60]

I dunno I service an '07.5 6.7 and it's also around 240k. It's developing some pretty noticeable oil leaks, esp topside somewhere.

But yeah, the old 5.9s can become real oil slicks.

 

[Dino01]

That’s why the old 5.9s and Mercedes 616/617 diesel engines last so long compared to everything else, all the leaks rustproof the engines and ensure the oil is constantly refreshed

Longevity engineering 101

 

[The motor guy]

I dunno I service an '07.5 6.7 and it's also around 240k. It's developing some pretty noticeable oil leaks, esp topside somewhere.

But yeah, the old 5.9s can become real oil slicks.

Maybe the 1999 is just a lot older.

 

[Bighorn2500]

2012 6.7L needed oil pan gasket replaced at 179,500 miles due to leaking.