How many miles on your Cummins diesel?

[94-Newmar]

As mentioned in a previous post.. are we factoring in miles/time to rebuild or upon major failure due to wear? Are we referring to motorhome or OTR platforms?

Regardless, there are some differences between the two heavyweights Cat/Cummins in the motorhome platforms. The usuals are the Cat 3126e, Cat C7 and the Cummins families ISB/ISC/ISL/ISM. As far as longevity goes, yes, it's most likely the Coach is going to fall apart before either requires a major rebuild unless you use yours as a daily driver going from coast to coast. That being said, when it comes time for a rebuild the Cummins families are completely rebuildable while the Cat counterparts are generally throw-away at that point. Caterpillar did not use a cylinder sleeve in their 3126/C7 platform - exactly like gasoline engines. When the piston/rings wear down the cylinder you're wearing down into the block itself. There are some oversive pistons available, but the cylinder walls at that point are beyond recommended tolerances. Cummins uses a replaceable wet sleeve system which allows the mechanic to simply order 6 new sleeves and install them with a new piston/ring assembly. Basically in layman's terms it's a replaceable wear surface. So unless you spin a crank, cam or rod bearing which causes wear to those surfaces beyond oversize bearing availability you can most likely rebuild and obtain another xxx,000 miles out of it. Again... your coach is most likely going to be 40+ yrs old at this point! :-)

[JHowell]

1999 Monaco Dynasty 219000. Will out live me.

[NHRA225]

Originally Posted by Mutt

Second owner 74,000 mi. Don't mean to hijack the post, but does anyone use the Lucas Oil Additive when changing oil? My unit is a 2002 Cummins 8.3L and is one of the models where Cummins placed the CrankCase Vent outlet just below the exhaust manifold. When the PAC Brake is used very much the drip pipe lets the heavy oil vapor drip out and can use as much as 3-4 qts in a very short time. Of course Cummins had a so called "Campaign" where they came up with a fix if you happened to find out about it. Since I bought used, the "Campaign" had expired. So, I have been adding 2 to 4 qts of the Lucas at oil change intervals, that seems to help with the oil loss, expecially when the PAC Brake is used. Any one know if these thick additives hurts the engine?

Been using Lucas 15/40 High TBN since 2000 when I bought it. I also add in 2 qts of the Lucas Oil Stabilizer at every change, As I mentioned before my Oil Analysis from this past May was a near perfect score, You are correct that constant use of the PAC Brake will cause blow-by and puking of a little oil, My Engine pukes about 3 oz every 2000 miles or so, not a big deal !

[dakratdave]

Originally Posted by 94-Newmar

As mentioned in a previous post.. are we factoring in miles/time to rebuild or upon major failure due to wear? Are we referring to motorhome or OTR platforms?

Regardless, there are some differences between the two heavyweights Cat/Cummins in the motorhome platforms. The usuals are the Cat 3126e, Cat C7 and the Cummins families ISB/ISC/ISL/ISM. As far as longevity goes, yes, it's most likely the Coach is going to fall apart before either requires a major rebuild unless you use yours as a daily driver going from coast to coast. That being said, when it comes time for a rebuild the Cummins families are completely rebuildable while the Cat counterparts are generally throw-away at that point. Caterpillar did not use a cylinder sleeve in their 3126/C7 platform - exactly like gasoline engines. When the piston/rings wear down the cylinder you're wearing down into the block itself. There are some oversive pistons available, but the cylinder walls at that point are beyond recommended tolerances. Cummins uses a replaceable wet sleeve system which allows the mechanic to simply order 6 new sleeves and install them with a new piston/ring assembly. Basically in layman's terms it's a replaceable wear surface. So unless you spin a crank, cam or rod bearing which causes wear to those surfaces beyond oversize bearing availability you can most likely rebuild and obtain another xxx,000 miles out of it. Again... your coach is most likely going to be 40+ yrs old at this point! :-)

This is not quite true.Last winter my isb 300 hp dropped a valve seat at42000 miles.Scraped up cylinder .This not a sleeved motor so had to install a long block.

[94-Newmar]

Originally Posted by dakratdave

This is not quite true.Last winter my isb 300 hp dropped a valve seat at42000 miles.Scraped up cylinder .This not a sleeved motor so had to install a long block.

Indeed, I stand corrected due to lack of coffee this morning while posting. The ISB is not sleeved in either the 5.9 or 6.7L configurations. The C/ISC/ISL/ISM/ISX are indeed sleeved.

[becks]

Originally Posted by HicksRA

I don't think I'd ever be able to afford enough fuel to wear my Cumming ISL out...

+1 With proper maint few of us will ever be able to afford enough fuel cost to ever wear one out. Most important factor in diesel ownership is maint, and many owners do not understand that.

[docj]

I'm pretty sure the larger CAT C-12 and C-15 engines have sleeves. I don't know about the C-9.

[Cat320]

Originally Posted by MSHappyCampers

I have been under the assumption that MH diesel engines typically go 500,000 miles. Yesterday I was talking to a guy who managed a trucking company all his adult life, and he says that the Cummins diesel typically only lasts about 250,000 to maybe 300,000 miles, whereas the Cat diesel will last a lot longer. What has been your experience on this?

Doesn't make any difference. How many of us will drive our MHs even100k, much less "only 250k to 500k."

[joeplazek]

1996 Monaco Signature 40ft Cummins 450eplus 45,000miles

[Borderbuster]

1993 cummins 8.3 300+hp. 156,000 miles, I am 3rd owner. Still running perfect and I expect (know) it will outlast me.

[pumper9x9]

2002 ISL 400 90k