Mid-OCI oil sample of RT6 CK-4.
From Polaris:
Truck Odometer: 388000 mi
Miles on oil: 36000
10 quarts of makeup oil added. That is 9 quarts burned, and 1 quart fresh when the filter was changed mid-OCI.
Fram Ultra filter for first 18k, Purolator Boss for 18k.
Wear Metals:
(Element (ppm); 235k, 322k, 338k, 352k, 370k, 388k)
Iron; 42, 52, 30, 50, 38, 72
Chromium; 3, 3, 1, 2, 1, 2
Al; 4, 5, 3, 4, 3, 4
Cu; 3, 4, 1, 2, 1, 3
Lead; 9, 31, 4, 7, 2, 13
Contaminants:
Silicon; 6, 13, 7, 9, 7, 8
Sodium; 8, 6, 5, 4, 7, 9
Potassium; 62, 0, 1, 1, 4, 1
Multi-source metals:
Moly; 75, 76, 5, 4, 0, 2
Boron; 83, 38, 112, 69, 106, 62
Additive metals:
Mag; 1333, 1198, 179, 163, 94, 105
Calcium; 960, 1111, 2174, 2198, 2053, 2179
Phos; 1138, 1104, 1012, 1048, 924, 959
Zinc; 1439, 1471, 1277, 1271, 1143, 1211
Fuel Dilution; <1%, <1%, <1%, <1%, <1%, <1%
Soot; <0.1%, <0.1%, <0.1%, 0.4%, 0.3%, 0.7%
Water; <0.1%, <0.1%, <0.1%, <0.1%, <0.1%, <0.1%
KV100 (cSt); 15.1, 15.1, 15.3, 15.3, 15.4, 15.4
TBN; 6.54, 6.99, 5.69, 4.27, 4.96, 4.13
Oxidation; 15, 16, 14, 14, 13, 15
Nitration; 10, 10, 9, 9, 8, 9
Polaris Comments:
Flagged data does not indicate an immediate need for maintenance action. Continue to observe the trend and monitor
equipment and fluid conditions. LEAD is at a MODERATE LEVEL and may be OVERLAY METAL from MAIN/ROD BEARINGS; Iron is
at a MINOR LEVEL. IRON SOURCES in engines can be cylinder liners, iron pistons, hardened steel camshafts, crankshafts, gears,
hardened rocker arms, valve bridges, alloyed steel cam follower rollers, etc. Lubricant and filter change acknowledged. Sample
information has been added or tests have been rerun or additional testing was added and the report has been regenerated.
Another Lead spike, and for no apparent reason, which Polaris has flagged at a moderate level. And the Iron of 72 ppm was flagged as minor. Soot continues to increase, although Polaris didn't flag it as a concern.
Corrected Iron concentration is 137 ppm due to the 10 quarts of makeup oil, yielding a wear rate of 3.6 ppm per kmile. This is significantly higher than the 3.1 of the last sample. Based on one data point, it seems that the wear rate increased by 18% over the 2nd 18k miles. I think I will shorten the interval of the new oil fill to 30k.
2001 Dodge 2500, 388k miles, 36k OCI on RT6
- Thread starter A_Harman
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That's a very long OCI, but with it running well at 388000 miles you can't argue with the results.
You've got enough data to see a trend towards higher soot levels. Could it be time for new injector nozzles?
Overall, everything looks more or less consistent and probably not too bad for a truck that actually does some work. To get an idea of how hard this engine is run, what is the rated HP, the average weight being hauled and your fuel consumption per mile/hour?
Comparing your data to the 4BT UOA I had done back in January, it seems that our chore tractor's life has been a piece of cake over the last 6 - 7K hours. I hope to post my report soon.
I have begun thinking about doing something with the injectors, but I haven't detected any decrease in fuel economy or excessive smoke, so I'll just monitor the trend for now. These injectors were installed at 193k miles, and are +40HP "RV275" units, as they are called in the diesel performance aftermarket. But they are genuine Cummins injectors, so I have confidence in the quality.
This truck is in commercial service delivering travel trailers all over the US and Canada. So far, I have towed trailers in the range of 4000 to 11,000 pounds, but the truck is rated for up to 14,000 pounds. I tow either frame hitch or 5th wheels. The frame hitch trailers are 8' wide x 11' high, and the 5th wheels are 8.5' x 12'. The "average" trailer for me is 27 ft long, weighing 7000 pounds. I typically run at 65 mph, 2100 rpm when I am towing, and 75 mph, 1900 rpm when I am running unloaded. Par fuel economy is 11 mpg loaded, and I have seen a range of 7.5 to 12.5 mpg, depending on wind, terrain, and cruise setting. I have enough power to run 70+ mph loaded, but fuel economy takes a big hit. They don't pay for fast delivery in this business, so the goal is to minimize operating costs, therefore I run slow. Unloaded, I am getting 21 mpg consistently, and that has never been better in the 14 years and 340k miles in which I have owned the truck.
Thanks, it is very interesting for me to hear about that type of business. Your 6B definitely does some work if you are burning like 6 gal./hour. Please keep us updated.
dnewton3
Staff member
Regarding the UOA; good results overall. The soot, while possibly elevated over other samples, is no where near any concern level (typically 3.0 or 3.5% for most major diesel manufacturers).
Regarding the fuel economy and service factor, that's also pretty typical. My stock Dmax gets about the same mpg pulling my RV, and the best I've got unloaded is around 20mpg. Pulling heavy loads with large frontal areas is VERY speed sensitive.
RV trailer length really has little to do with the fuel consumption, except in an indirect manner. Longer rigs do weigh more, so that part certainly figures into the equation in terms of rolling resistance. But the length itself does not matter a whole lot. IOW, if one trailer weighed 8000 pounds and was 25' long, and another also weighed 8000 pounds but was 29' long, as long as the frontal area were similar, the wind load will be similar, all other attributes held the same. Once the high-pressure area is produced at the front, and then the low pressure area collapses along the body of the trailer, the length past that point does not affect the air resistance load much ( i.e. fuel economy). Admittedly there's a slight differential in surface drag for a longer rig, but that is so small it would be impossible to detect in daily operation. Wind resistance increases as a square of the speed. Double your speed; quadruple your drag. And the "power" needed to overcome that is factored in too, because work (real physics definition here, not layman concept), = work/time. Double your speed not only squares the wind load, but also cuts the "time" in half! Power requirements are GREATLY affected by vehicle speed. The pulling force required to move the RV down the road = rolling resistance (based on weight) + air resistance (based on frontal area, Cd and speed) + headwind (if present). "Power" consumes fuel, so the faster you go, the more it hurts!
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All good observations, dnewton3. I have found that I can get 8.5 mpg towing an 18-foot, and 12 mpg towing a 31-foot. I had the 18-footer going to Billings, MT this summer. West of the Mississippi, the speed limits go up. The speed limit in South Dakota is 80 mph, and I felt like an idiot running 65, with all of the big rigs blowing by me at 75. So I kicked it up to 72 and ran double overdrive. Yep, 8.5 MPG with an 18-foot trailer. When I was running 65 through Illinois and Wisconsin, I was getting 11.5 MPG.
The thing that really surprised me was fuel economy with 5th-wheels. Despite the larger frontal area, I get better fuel economy with a 5th-wheel compared to a ball-hitch of comparable length and weight. And the 5th-wheels are much less work to tow. They are much less susceptible to crosswinds and the bow wave effects of big rigs than are ball-hitches. I think this may be due to lower overall coefficient of drag when mated to the tow vehicle, and perhaps secondarily due to lower tire rolling resistance.
dnewton3
Staff member
5vers actually do well because of the frontal area not falling way so much as with a traditional trailer.
Pick-up trucks have a staggered frontal area (first the grill, then the windshield). The first large low pressure area develops behind the cab over the bed. That increases the effect of a second high-pressure bubble developed by the front the RV, then another low pressure area along the sides, top, bottom of the RV, and yet again at the tail of the RV. When pulling a 5ver, that low above the truck bed is partially filled, and eases the transition of the pressure drop up to the roof of the RV and along the sides. But the 5vers ease the disparity of high/low transitions. I've not pulled 5vers, so I cannot directly make a contrast of "feel". But I take your word for it.
Want low drag? Get a pop-up. 
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Originally Posted By: dnewton3
But the length itself does not matter a whole lot.
As anyone can imagine, it can make going down the road in a straight line difficult (depends on wind speed of course). I get far better fuel mileage if the wind is punching my truck square in the nose rather than pushing it sideways. Crosswinds make for a long, bad day when the truck is 13'+ high and 72 ft long. 
I would expect that the shorter trailers would be a benefit to you guys pulling trailers with a pickup truck. Maybe not when there's a few feet difference, but several feet or more (shorter) should be a considerable help in reducing the engine's load. Again, talking specifically about driving in crosswinds.Originally Posted By: A_Harman
The speed limit in South Dakota is 80 mph, and I felt like an idiot running 65, with all of the big rigs blowing by me at 75.
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dnewton3
Staff member
Originally Posted By: dustyroads
Originally Posted By: dnewton3
But the length itself does not matter a whole lot.
As anyone can imagine, it can make going down the road in a straight line difficult (depends on wind speed of course). I get far better fuel mileage if the wind is punching my truck square in the nose rather than pushing it sideways. Crosswinds make for a long, bad day when the truck is 13'+ high and 72 ft long.
I would expect that the shorter trailers would be a benefit to you guys pulling trailers with a pickup truck. Maybe not when there's a few feet difference, but several feet or more (shorter) should be a considerable help in reducing the engine's load. Again, talking specifically about driving in crosswinds.
No argument, Dave. It's just that wind is a sore subject for me. I can moan and groan endlessly about wind and the money it steals from me. I couldn't help myself yapping as I did. 
dnewton3
Staff member
Originally Posted By: dustyroads
No argument, Dave. It's just that wind is a sore subject for me. I can moan and groan endlessly about wind and the money it steals from me. I couldn't help myself yapping as I did.
Originally Posted By: dustyroads
Originally Posted By: A_Harman
The speed limit in South Dakota is 80 mph, and I felt like an idiot running 65, with all of the big rigs blowing by me at 75.
Completely off topic, but hauling RV's, do you notice better build quality from one brand to another? I ask as I have a 5th wheel toy hauler which I am happy with so far, but there are some pretty depressing stories on RV forums about poor build quality of certain brands.
Of course if you can't answer due to job security, I understand.
Originally Posted By: 02SE
Completely off topic, but hauling RV's, do you notice better build quality from one brand to another? I ask as I have a 5th wheel toy hauler which I am happy with so far, but there are some pretty depressing stories on RV forums about poor build quality of certain brands.
Of course if you can't answer due to job security, I understand.
As an aside on travel trailer aero and other.
A 40% penalty is par. 1967 or 2017. 48% is fairly high, but not inconsistent with other reports. It can be bettered. Sub-40% is the province of aero TTs. When I bought my previous Silver Streak (a 1983 34') ten years ago I made comparisons with other early HPCR Cummins powered Dodge owners:
Where the TT was from 28' to 35' in length and weight ranged from 7,000 to 11,000-lbs; and where operators were running 58-62/mph in other than mountainous terrain, the average was from 14-16/mpg. Most of those were Airstreams. Some Avions. This was about double my early experience nearly fifty years ago. I might miss a high compression Chrysler TNT V8-440 under the hood, but not the towing mpg. Even with these TTs it was 7-10/mpg.
All these brands have lower ground clearance. All edges are radiused. One might say that the winds "pull" at them as they pass over the sides, instead of gathering force and "pushing" as with those taller, square-edged trailers.
I find I can hit 15-mpg towing as an average pretty easily with this 555 motor. 17 is the goal (latest is a 1990 35'; 9k GVWR). I've thought about re-gearing to the current 3.42 from 3.73 and just run in Direct while towing (NV5600 man trans). The solo average is 24. Have seen 27 numerous times, but I run slowly. (Truck TARE solo is 7,940-lbs these days. Within 40-lbs at all four corners. Trailer is close to that).
FWIW, front axle Load restoration when setting WD hitch is a bonus not just for handling/braking, but for mpg. The real culprit is steering slop. From column shaft all the out to the wheels (and free-spin hubs if 4WD). Kenworth cites steering corrections per 100-miles as a measurable problem. That's worth your time.
I was down on the Texas coast for years. Thus evacuation called for planning. That 36-gal tank at 80% meant 29-useable. Thus a range to 430-miles. But, it in the event of 3-5/mpg jammed highway, it would be not quite enough to get to the magic 150-mile mark where services could be presumed normal. I might buy a gasser today, but that kind of fact keeps me in mine. Still haven't gotten the 56-gal tank.
As to crosswinds, it's the 3/4's winds that are a bear for mpg. I hate it in the Kenworth, even with a tanker. But for travelling, this trailer type will continue on down the road in 40-mph constant. It's the gusts over that get ones attention, ha!
That said, I added a rear antisway bar from Helwig and upgraded the front. A Panhard Rod from Henderson's line-up is on the list. I highly recommend polyurethane antiroll bar bushings if you haven't changed out yours. The change for me is that (with a Hensley Arrow hitch) I don't feel a passing trucks bow wave until it hits the 8' bed and cab-height topper. (2WD with IFS plus rack & pinion steering). Now, the body isn't moving against the suspension. I might not notice the wind unless I pull over and it tears the door away from me on opening.
OP, you might enjoy the posts on www.airforums.com by VernDiesel. He runs an EcoDiesel in your line of work. Just hit 350k hauling Airstreams. Next to no repairs.
I've been running Rotella as it's what Terry Dyson recommended. I switched to T6 as even in hot Texas the engine starts easier. Baldwin filters otherwise. 10-15k intervals, but usually on an annual basis instead. Oil consumption is nil. I'm at just over 5000-hours on this 10,000-hour engine.
FP60 Fuel Power or Howes Meaner Cleaner most every tank. I find a noticeable difference in throttle response.
I see I can now order Schaeffers from Amazon so I'll switch everything over, to the 9000 oil and 2000 fuel additive. The latter makes rocket fuel, IMO.
Truck now at 220k with $500 in repairs in my ten years of ownership. Tires (Michelin) and brakes last over 100k. Original clutch, etc. What's not to like about a CTD?!
Best of luck to you on what I know is no easy job.
(And I recommend the PURPLE brand Extreme seat cushion plus lumbar for an old man's backside. Won't wear out and disappears those cracks in the road).
.
dnewton3
Staff member
If you recall, my last UOA series had some BRUTAL headwinds for the entire day(s). Ran around 1100-1300F for EGTs (pre-turbo). My fuel economy sucked badly.
I just got back from another RV camping trip. This most recent trip had nearly still air; very little wind at all. At the same 65 mph, instead of 1100-1300F EGTs, it was a steady 850-900F. WOW WHAT A DIFFERENCE. Fuel economy shot up a few mpg.
This is the best real world manifestation of how to realize the effect of speed (and wind), in terms of air drag. Remember that air resistance increases with the square of the velocity (an expoent of 2). Double your speed; quadruple your wind resistance. So driving 65 mph into a 30mph headwind is a BIG deal.
dnewton3
Staff member
Yes - it was brutal headwinds; sustained 20mph and gusts up to 30mph, for all flippin' day on I-90, and I-80 the next day.
In my UOA for this past year, the Fe spiked a bit. Nowhere unsafe, but a tad higher than the mean (but still inside of normal expected variation). Makes sense when you're running probably I would estimate 60%-90% throttle all day long, accounting for the headwinds, the speed, and the rolling hills in the plains of SD and IA. It's just a hobby for me, pulling my RV on vacation. But this is NORMAL for people whom haul loads and big rigs for a living; it's a fact they cannot avoid. Sometimes the wind will be at your back, or it may make your day miserable.
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