CM871 poor power and fuel econ

[Rawze]

(09-21-2022 )Grounded Pilot Wrote:  

(09-20-2022 )Rawze Wrote:  coolant system contaminant or additive?.

and why is the oil so black and nasty?. Looks like the whole engine is saturated with soot. - That is not normal either unless the EGR is active and no one is changing the oil often enough vs. its fuel economy.

I put new trans cooler lines and heater core lines on it last winter. Blew a line so figured I’d replace them while I was greasy. But I drained the coolant and refilled it with a 50/50 mix of the red final charge OAT coolant. Water filter was replaced after these photos. No telling really what was in the coolant prior to when we purchased it. We have figured out that it was a fleet truck so I’m betting it was getting the 50k between oil changes treatment. I’ve ran it for 100k miles and we change it every 12-15k with delvac. And I’ve been replacing half a gallon with 80/90. I haven’t put any oil additives (except 1 gallon of Lucas in the first oil change) in otherwise and have not put anything but the final charge pre mix in if I needed to add coolant.

As far as neglect goes, if this thing had a voice I’m sure it’d be screaming for help. But it’s revealed enough since I’ve been working on it to know it has had a rough life. She’s in rehab though!

Is there any oil additive that actually helps clean the internals out?

Do your next 3 oil changes at 3-4k mile intervals. Drop a 1/2 gallon of diesel into the oil and run it around the block a mile or so just before oil change. That is the cheapest way to flush all the years of soot out of it.

After those 3 oil changes replace the oil at intervals based on fuel mileage.. and not some dumb random number mileage like you mentioned.
here is a reference:http://rawze.com/forums/showthread.php?tid=8117&pid=70681#pid70681

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As far as the coolant system goes.. nothing beat 'Cumming restore' when used exactly as directed. It will flush the coolant system out. -= follow it up with a couple water-only flushes (few miles of driving it around at a time).. and then put regular 50/50 red in it and stop putting any other additives in there.

Use the coolant filter that does NOT have the sca impregnated into it. Cummins makes both types.. make sure you have the one that is not putting additives in there.