CM871 suddenly started using oil

What is a CM871?

 

Bobby this thread might be helpful to you:

http://www.thetruckersreport.com/tr...3-cummins-isx-cm871-technical-discussion.html

KH

 

I don't know why people can't just simplify and say what the engine is in the subject thread, then go more advanced.

 

Heavyd: We have a NTP warranty on it, but the Cummins warranty has expired.

WildHog: Other than the first couple of trips, it's had the same driver in it. We had the dealership do the first PM on it and the oil filter was incorrectly installed so it was leaking badly at first, and yes, there were big puddles under the truck. It was replaced and there haven't been any noticeable leaks since then. There is no report of it smoking and the EGR is still active. I actually passed the truck as it was coming in and I was going out. I didn't notice any smoke either.

TheChallenger: I've read that thread and there is a lot of useful information in there. I actually spoke with Rawze when we first purchased the truck on things to look for and potential issues with all of the DPF and EGR parts. Maybe I need to go back and reread it, but I don't remember reading anything specific to oil consumption other than Rawze recommended Shell over Delo or Delvac.

freightlinerman: I did state what the engine is in the title of the thread. The CM871 is a specific series of the Cummins ISX15, just like a 6NZ or SDP are specific series of the Caterpillar C15.

 

CM871 basically just refers to what EPA requirements are on it. CM570 is pre-EGR, CM870 is EGR, CM871 is EGR and Aftertreatment, CM2250 is EGR, Aftertreatment and SCR. I'm sure there is more to it but at its simplest form thats it.

Loss of oil without signs of external leaks can be very time consuming. Something that may give you a decent in sight to the possibilities is to have a dealer or cummins hook up to the ECM and review the "Aftertreament History". The ECM saves the last 10 regens, and what they can do is look at the time stamp on the regens and find out how long the unit is going between regens. I'm not 100% sure on the gap between regens but the ECM will automatically initiate a regen after 96 hours ECM time (I believe that is still correct). So if you were to build a table 96 hours would be perfect and the closer you get to 1 hour would be the worst. Now if you are in the "Below 20 hrs" range between regens then liner scuffing could likely be in play. This is not a definate answer but is where I like to start when trying to gauge problems in the engine. Now someone has mentioned earlier about valve stem seals and I agree that would be something to check IF AND ONLY IF ALL OTHER EXTERNAL LEAKS AND POSSIBILITY OF LEAK IN TO COOLING SYSTEM, AND FUEL SYSTEM (fuel system is highly unlikely) have been verified. i only say that because once you start looking internally you start talking about major tear downs. So in order of checks:
1. Externally
2. Exhaust of Turbo
3. Compressor side of Turbo
4. Oil from Air Compressor
5. Oil in Coolant
6. Oil in Fuel (again highly unlikely)
Once all these have been verified
7. Valve stem seals
8. Liner scuffing

Unfortunately I've seen more liner scuffing issues than anyone wants to admit to. Also a simple blowby test more times than not will NOT show oil consumption. The only way to verify is to remove the pistons and inspect the liners. What happens is the rings make smoothe shiney spots on the liners but still keep good compression in the cylinders and thats why a blowby test does not disprove liner scuffing. The quick change is oil consumption can be skewed due to the possible change of duty cycles maybe your drivers dont have identical routes as the previous owners.

 

Thank you for all of the information from everyone. Everyone basically confirmed what we knew but started to question because of the dealerships comments.

Update:

We ended up taking the truck to Crosspoint Cummins last Monday, since the KW dealership wouldn't even look at it. They seemed much more understanding and agreed that there was too much oil consumption and even let us know that there was still Cummins warranty on it until 500k miles and that there was a service advisory that Cummins put out concerning an issue with polished liners. The down side was they couldn't get it into the shop until Thursday. They've been a little slower than what we would have liked, but we talked to them today and they said they found two liners that were being polished and should start putting it back together today or tomorrow and it should be ready by the end of the week. We are still waiting to hear what Cummins or NTP come back and say about coverage.

 

Make sure the injectors get replaced. We have had a few cases like this and found the injectors to be over fueling, or the spray pattern is bad causing fuel build up on the liner wall which burns into carbon which gets packed into the rings which leads to the polishing. I also recommend that all 6 six liners packs get replaced to keep everything even and balanced. Don't be surprised if warranty only pays for the two they found bad. You may have to pay out of pocket for some parts, but the labor should be basically free since everything is apart anyway.

 

Heavyd,

Thanks for the additional information. I'll need to call them back and find out if they are just doing the two or if they are going to do a six pack on the liners and injectors. Communication has been a little frustrating as well.

 

Yes, warranty jobs like this can be very frustration for the person who owns and operates the truck because they end up being the 3rd person in the deal. In the relationship between repair shop and customer, you get pushed out of the loop sometimes, because since Cummins is paying the bill, they are in fact the customer, not you. Hopefully the repair shop treats you right. Just keep on them.

 

Update: All 6 wholes got new piston kits under Cummins warranty. It took them two weeks before we got the truck back. That part was disappointing. The truck is back out working and the driver reports that it feels like it's pulling stronger. With only 1,850 miles since the overhaul, the driver has had to add 2.5 gallons of coolant, so there's a leak somewhere. He's going to stop in Denver and have it looked at. Hopefully it's not an internal issue and just the after treatment cooling system that didn't get put back together properly and will still be covered under their warranty. We'll be making certain they check the DPF to see if any coolant made it through and started to crystalize and clog the filter.