Engine/Transmission (1994 - 1998) Clean Valve Covers

[fortunate1]

Just finished with the latest valve lash check/adustment. Most were still right where they were from the last time, but I went ahead and re-adjusted all of them anyway. I was amazed at how clean the inside of the valve covers were. Just a very slight grayish film that easily wiped away with a clean rag. I have never cleaned the inside of the covers before. Past valve lash adjustments were at: 30K, 60K, 113K, and now at 190K miles.



I've had the valve covers off from other engines with much less milage (v-6 from s-10, 4-cyl from saab, and o-twin from bmw bike), but none were as clean as these from the Cummins. I guess I'll check them again in 75K to 100K miles.

 

[Mike Ellis]

What kind of oil have you been running Fortunate1?

 

[Blakers]

From my personal observation over the years I've found diesel engines always are much cleaner inside than gasoline engines.



I presume there's less contamination in the blowby from combustion than in the gasoline engine.



Blake

 

[fortunate1]

Oil

I used to change the oil with Rotella 15W40, but for the last 50K or so I've used Delo 400. Most always with a Fleetguard filter (3449 or updated 3552), but have to admit that once or twice I did spin on a brand-F filter. Oil is pretty clean at change time - 6000 miles.

 

[Roger Ledbetter]

My oil is always black

and I have changed mine every 3,000. It turns black almost right away also.

What gives?

 

[Blakers]

Re: My oil is always black

Originally posted by Roger Ledbetter

and I have changed mine every 3,000. It turns black almost right away also.

What gives?

That is just the nature of diesel engines. Perfectly normal.



Blake

 

[illflem]

I really have to wonder when folks say their oil is clean, I've worked on diesels for close to forty years and have yet to come across even one that didn't turn the oil black in at most 500 miles. This is even with a bypass filter. I would feel like something was wrong if it didn't turn black.

 

[Roger Ledbetter]

I feel better now, thanks guys!

I want my engine to last a long time

 

[fortunate1]

illflem, keep on wondering. Mine's not a real big "smoker", so maybe that keeps excess soot production down. Just telling it like it is. Oil is slightly brown at change, definitely not black - I've seen BLACK oil from a ford 7. 3L at 500-600 miles.

 

[Gifford]

clean valves

Obviously you dont have a CA EGR equipped machine... THe EGR is so wonderful, it coats the entire intake side of the engine with a wonderful patina that thickens with time...

 

[fortunate1]

Oil gets black

If the oil gets black so soon (or even during full service life), what's that say about the filtration? The soot, etc. is not getting filtered out in these cases. That's not good for long life. Another cause for the black color may be short turbo cool-down times - that will burn the oil around the turbo bearings and form coke. That's not good either. I've always been able to easily read the level marks & words on the dipstick through the oil; it's never been so dark that it covered the markings.

 

[Blakers]

As I said before, it's perfectly normal for a diesel to turn the oil black in a relatively short time. I've been working with diesels for almost 40 years and almost every one I've seen has done this. We have a 1977 Ford 2600 diesel tractor that we bought new that kept its oil relatively clear between changes for several years.



The pigments that turn the oil black are way too small for any filter to catch. They are not a detriment to the engine, nor are they an indication the oil is bad or need of changing.



Blake

 

[illflem]

My feeling why the oil turns dark so fast in most diesels is because when you drain the old oil you never get it all out, it doesn't take much soot to dye the new oil. I sort of like it, makes it easier to read the dipstick.