RV News RVBusiness 2021 Top 10 RVs of the Year, plus 56 additional debuts and must-see units → ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > POWER TRAIN GARAGE FORUMS > Caterpillar Engine Forum
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Thread Tools Search this Thread Display Modes
Old 12-15-2010, 11:38 AM   #1
Join Date: Dec 2010
Posts: 94
Maintenance Rant - History of oil analysis

After significant time as a Technician, 25 years wrenching and now having engineering experience, I rant...

After being shocked to hear a CAT shop advise an RV owner NOT to maintain their RVs, especially the engine ($30,000 for a round number?), I rant.

I hope CAT is paying attention.

The Rant is about oil analysis - but - with a very important piece of history.

A Cat OMM (it was a Cat best I recall, OMM is the engine maintenance manual, small blue book) and best I recall, it was on the 3126. It may have been from a .PDF that Cat sent me on an engine maintenance question, but at any rate, it was from a big diesel engine manufacturing company common to RVs.

The manual clearly stated: 'Do not do oil analysis.'

But oil analysis is suggested by many shops and even DEALERS as an acceptable alternative to the MAINTENANCE REQUIRED BY THE ENGINEERS WHO DESIGNED THE ENGINE.

History. =========

Back in the early 1990s, computer software and maintenance practices in factories started to use someting called "CMM" software, a computerized system to track maintenance on machinery (and in factories in general). This is in the context of a manufacturing facility with extremely expensive equipment where one piece of equipment being down for maintenance shuts an entire line, or an entire plant down.

They cannot afford to have a plant down for half a day. They are out of business for a shift / day. They might count the losses in tens of thousands of dollars / hour.

They cant just shut a machine off to change oil. $250 worth of oil = 20,000 in lost production, just to pull numbers out of the air.

They also have engineers working in the plants and with the machinery, NOT just mechanics.

The factory mechanics and engineers religiously track machine data, daily, hourly, including something that came into vogue then - OIL ANALYSIS. (or at least it came into vogue to track it, it certainly existed before then)

Oil analysis was used in that context (and surely still is) to determine, not how the oil was doing (thats already known) but to know the absolute LAST MINUTE the machine could run, the last production schedule it could meet, before the machine had suffered bearing damage that would put the machine out of service for a longer and much more expensive period of time than the oil change and production losses.

End history=======

Now, to Cats website:

Cat Products & Services
(see the first and fourth documents, notice the title on the fourth - indicating what was written above about critical maintenance)

RV's are not factory production machines. They are not in service to haul millions of dollars in freight-miles per year.

Your RV, headed for AZ to be parked for two months is not a critical application, especially since it probably does not have more than 100,000 miles on it. It has mostly "down time."

Theres a risky rationalization, and Ive heard it from a CAT DEALER - "since your engine has very low miles on it, just ignore the factory oil change requirements. What were seeing out there doesnt justify it, just do oil analysis"


1.) Cats ENGINEERS (or cummins, or GM, or....) were the ones to design, build, test, consult with the oil company on oil type, chemistry, additive package, life span, temperature, acid attack, waste disposal..... (ad infinium, ad nauseum). NOT MECHANICS. They specify maintenance REQUIREMENTS. They are requirements, NOT SUGGESTIONS. They didnt consult with "what we see out here" or "in my opinion, oil analysis is good enough". They dont ask, they tell. They have mechanical, electrical, chemical engineering backgrounds and tribal knowledge that spans thousands of man- years.

2.) Oil analysis is not intended for your RV service. It was created and tracked as described above, for critical industrial operations. That someone who sells oil analysis wants to expand their sales into the RV market is irrelavent.

They're in it for the money, not the life of your RV engine.

3.) Mechanics and Techs are GREAT. Especially when the engine doesnt run and you need it fixed. Mechanics are in no case qualified to contradict the engineers that designed the thing in the first place.

4.) The excuse for ignoring maintenance REQUIREMENTS is that the engine (vehicle) have low hours/miles. IF there was an exemption for that, the engineers would have said so. It would be in the RVs engine OMM. It would appear on the Cat website as a "thus sayeth our engineers" statement. IT IS NOT THERE. I looked, I contacted Cats tech reps.

Its a "red herring" (evasive comment) to tell an RV owner that because we see trash haulers and semis that do this-or-that, that it applies to your RV. That is OPINION. Same engine (type) but a different service. If its acceptable to a companies fleet maintenance supervisor to run an engine till its about to blow up, thats their business, they know the risk and should have the money back to do an engine change.

I doubt most RVers have $30,000 in loose change in the sofa cushions for a major rebuild. Its 10K for a simple overhaul.

Lack of maintenance is no less important in an engine that doesnt run regularly. Not running regularly is engine abuse. The engine drains of oil when not run and causes dry starts. The Cat 3216 OMM manual (and the Onan 7.5 generator) requires a special storage procedure if the engine isnt run for two weeks (if memory serves, look it up).

Running or not running still leaves nasty things like sulfuric acid and metal shavings in the oil pan and filter.

Sure itll run to 100 - 150K miles when abused by not changing the oil. Same situation in a passenger car, ever wonder why most people push them over a hill at 100,000 miles? Lack of maintenance is the reason. Abuse shaves lots of miles off the top end. The mechanics and oil analysis companies telling to you ignore the engineers arent PAYING for that 300,000 miles of engine life (whatever it is) that are lost due to refusing to do maintenance.

Youre paying THEM when it goes "bang" due to lack of maintenance.

Remember, oil / filter changes are as much about the FILTER and to remove METAL SHAVINGS as the oil. You can just pull the dipstick and smell the oil to tell what condition the oil is in, with a little practice.

Ive responded to more than one RV seller who claims "well allow you to take it to a mechanic to have it inspected" (due to no maintenance records), with "will they do a teardown to inspect the bearings? Deer in the headlights...

Having been both a Tech that didnt listen, and an engineer who Tech refused to listen to (and they really didnt like "I told you so" but they heard it anyway), I can tell you that without dispensation from the Factory Engineers (not sales, not marketing, not a repair shop, not some phoney "NASCAR approval", not some new marketing agreement with an oil company) to change service and maintenance intervals, that a mechanics or shops advice to ignore maintenance is NEVER acceptable. They arent qualified to contradict engineering that originally designed the thing.

The technical problem with oil analysis is that it only detects trace amounts of things (metals, chemicals). Analysis cannot look into the past and see damage from a previous owners abuse. It cannot see large metal fragments in the oil pan that get sucked into the filter and cut the paper element apart, then let contamination through. They cannot see cracks in the filter element. Fram had a motorcycle oil filter that split in two at the seams, oil analysis wont find that. They used a metal crimp afterwards.

Case in point- automobile engine. I have a 78 Chevy Blazer that I maintain like its a religion. Just to stop a rear main seal leak during a clutch replacement (so engine oil couldnt contaminate the new clutch lining) I pulled the oil pan to change the rear seal. The rear main cap and bottom main bearing shell came down. On an engine with 210,000 miles, there was absolutely no wear on the bearing surface except for the oil wedge (slight wear from the oil jet coming out of the oil port). The rest of the bearing surface looked as if it just came out of the box. The matte finish was all there.

But, I change oil about every 3,000 AND at each season, 10-30 in the fall, 10-40 in the summer. Thats not in the books. I change oil due to mileage, and to optimise the engine oil pressure for each season because I know that 10W40 is too thick in the winter to pump easily at a cold start. The engine should see 500,000 miles without an overhaul. I know of one thats at 390,000 from similar maintenance. I fill the filter so the system isnt pumping AIR at startup. The shop wont do that...

Next time someone offers oil analysis, or anything else contradictory, ask this simple question:

"The engine manufacturer REQUIRES (pull the OMM out of your pocket) oil and filter changes every 12,000 (9-15 depending?) or no longer than a year (1 yr, Cat, 6 mo. Cummins). You are advising I ignore the engineers requirements and rely on your oil analysis. Will you sign an agreement to be responsible for any damage that occurs from ignoring the engineers requirements?"

Watch them panic. The deer in the headlights look is priceless...

What oil analysis and oil filter shaving counts indicate is that DAMAGE HAS ALREADY OCURRED. Why not prevent it in the first place?
davecampbell is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 12-15-2010, 11:56 AM   #2
Administrator in Memoriam
Route 66's Avatar

Newmar Owners Club
Retired Fire Service RVer's
Spartan Chassis
Join Date: May 2000
Location: Newark, DE
Posts: 25,899
My rant is just bit shorter.

I agree!
Adios, Dirk - '84 Real Lite Truck Camper, '86 Wilderness Cimarron TT, previously 4 years as a fulltimer in a '07 DSDP

Route 66 is offline   Reply With Quote
Old 12-15-2010, 11:57 AM   #3
Senior Member
Winnebago Owners Club
Freightliner Owners Club
Join Date: Aug 2006
Posts: 1,500
Count this as an Amen from the choir.
MaverickBBD is offline   Reply With Quote
Old 12-15-2010, 12:16 PM   #4
a k
Registered User
Newmar Owners Club
Join Date: Jun 2009
Posts: 1,142
You are right. I did heavy HVAC maint for 30 years and we took oil samples of big machines AT TIME OF OIL CHANGE. We changed the oil yearly before winter and if the samples came back bad we knew to tear it down and fix the problem BEFORE it tears up.

Also if you have a ext warranty, kiss it goodby.
a k is offline   Reply With Quote
Old 12-15-2010, 12:21 PM   #5
Senior Member
dons2346's Avatar
Country Coach Owners Club
Join Date: Dec 2010
Posts: 6,307
Oil analysis us useless unless it has been done from the beginning. It is used to set a pattern of wear and unless you have a baseline..... well......

I think people have it done just to show they are anal when it comes to maintenance.
dons2346 is offline   Reply With Quote
Old 12-15-2010, 12:25 PM   #6
Senior Member
JC2's Avatar
Newmar Owners Club
Texas Boomers Club
Join Date: Dec 2003
Location: Mo/Texas
Posts: 3,496
I agree also. Nothing like good ole common sense preventive maintenance.
2010 Newmar Dutch Aire DP 4304-Cummins ISL 425hp-Spartan MM Chassis-2013 Chev Equinox AWD-Ready Brute Elite Towing System-FMCA 402879-SKP 120487
JC2 is offline   Reply With Quote
Old 12-15-2010, 12:50 PM   #7
Senior Member
Winnebago Owners Club
Join Date: Dec 2009
Location: Las Vegas, NV
Posts: 841
I disagree almost completely. Very seldom does oil "wear out", just gets bad stuff in it.

Analysis tells you when you are approaching too much bad stuff. Then it's time to change.

Just saying.....

two-niner is offline   Reply With Quote
Old 12-15-2010, 02:14 PM   #8
Senior Member
powerboatr's Avatar
Damon Owners Club
Freightliner Owners Club
Join Date: Mar 2006
Location: North East Texas
Posts: 4,698
Originally Posted by two-niner View Post
I disagree almost completely. Very seldom does oil "wear out", just gets bad stuff in it.

Analysis tells you when you are approaching too much bad stuff. Then it's time to change.

Just saying.....

in fact your are right.......
oil doesn't wear out. the additive package does.
we in aviation and other places like factories and powerplants do oil analysis to track the beginning to the end of a piece of gear, (engine, transmission, etc)
oil change intervals are set by hours....not oil analysis.
analysis tells us of impending failures of bearings and guts and additive levels
then based on the tests, the oil is either changed EARLY or not
but it is never run past the hard HOUR clock.
sometimes the results are to flush the oil system, refill, run xxx hrs and retest....then based on results it s change of unit or re-sample again at prescribed times....or back to normal intervals.
but never ever is OA used to extend oil change intervals, except in a new type of equipment during its pre-production phases and periodically in its post production test phase
USN Retired, Life time member of the DAV.
Enjoying the 2008 Damon Tuscany 4056, #3998 no your eyes are fine, there are really 6 slides
2016 Expedition or 2012 Edge toads

powerboatr is offline   Reply With Quote
Old 12-15-2010, 03:28 PM   #9
Senior Member
Winnebago Owners Club
Join Date: Dec 2009
Location: Las Vegas, NV
Posts: 841
Powerboatr: "Back in the day" when B & C model's came out. The turbine lubricant was mostly mineral oil w/additives. Never changed until TBO.
At times, hot starts were the norm. Pure excitement!!

two-niner is offline   Reply With Quote
Old 12-15-2010, 03:39 PM   #10
Senior Member
Join Date: Jul 2010
Posts: 871
I agree.

Always RTFM.
WOODYDEL is offline   Reply With Quote
Old 12-15-2010, 06:00 PM   #11
Senior Member
sailor_lou's Avatar

Nor'easters Club
Join Date: Jun 2007
Location: CT
Posts: 921
Dave is on a roll today and I couldn't agree more. I still replace my car/truck oil every 3k miles, which is probably overkill, but I am getting over 300k miles on my engines and none of them have needed a rebuild or burn oil. Can't argue with success.

05 Travel Supreme 38DS04, CAT C-7
sailor_lou is offline   Reply With Quote
Old 12-16-2010, 12:12 PM   #12
Senior Member
deandec's Avatar

Country Coach Owners Club
Join Date: Jan 2006
Location: Northern California
Posts: 4,869
I would guess that all engine manufacturers:

1. Test their engines for maintenance cycles based upon their average known use.

2. Most of their road transport engines run anywhere from 24/7 to 8 hours per day. (Over the road hot seated trucks to garbage collection or UPS delivery trucks.)

3. A low percentage of their engines are employed in low use environments such as motorhomes or seasonal trucking. Oil change issues on these applications will not likely manifest themselves in the Warranty period.

4. Low use diesel engines will likely have the 5 year warranty expire before encountering a major failure.

5. Warranty coverage is the main reason Manufacturers publish maintenance schedules. It is a means of assuring the potential buyer that they make as good or better engine than the competition makes and establishes workable limits of the Warranty for the manufacturer.


I doubt seriously that the Manufacturer's engineering department has spent millions of dollars testing prototypes of their engines in a light or no duty cycle to determine how frequently the oil should be changed.

Instead, it is just simpler and much more cost effective to state something like "or once per year".

At most they are needlessly costing their buyers to spend $100 in materials and supplies plus some labor while appealing to some sort of buyer logic.
1995 38' CC Magna #5280
C8.3L 300hp Cummins, 31,000lbs
Gillig Bus Chassis
deandec is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Guardian RV generator oil leak...... Kash MH-General Discussions & Problems 14 11-09-2009 02:04 PM
Why oil prices will tank Hitchhiker iRV2.com General Discussion 46 12-07-2008 04:53 PM
Oil Analysis Oemtech Workhorse and Chevrolet Chassis Motorhome Forum 5 02-26-2008 03:14 PM
Oil Filter Change From **** DriVer Workhorse and Chevrolet Chassis Motorhome Forum 70 07-18-2007 06:24 AM

All times are GMT -6. The time now is 06:39 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.